BBC Two, Tuesday 26 November, 2002 9pm
Homeopathy: The Test
Homeopathy was pioneered over 200 years ago. Practitioners and patients are convinced it has the power to heal. Today, some of the most famous and influential people in the world, including pop stars, politicians, footballers and even Prince Charles, all use homeopathic remedies. Yet according to traditional science, they are wasting their money.
Sceptic James Randi is so convinced that homeopathy will not work, that he has offered $1m to anyone who can provide convincing evidence of its effects. For the first time in the programme's history, Horizon conducts its own scientific experiment, to try and win his money. If they succeed, they will not only be $1m richer - they will also force scientists to rethink some of their fundamental beliefs.
Homeopathy and conventional science
The basic principle of homeopathy is that like cures like: that an ailment can be cured by small quantities of substances which produce the same symptoms. For example, it is believed that onions, which produce streaming, itchy eyes, can be used to relieve the symptoms of hay fever.
However, many of the ingredients of homeopathic cures are poisonous if taken in large enough quantities. So homeopaths dilute the substances they are using in water or alcohol. This is where scientists become sceptical - because homeopathic solutions are diluted so many times they are unlikely to contain any of the original ingredients at all.
Yet many of the people who take homeopathic medicines are convinced that they work. Has science missed something, or could there be a more conventional explanation?
The Placebo Effect
The placebo effect is a well-documented medical phenomenon. Often, a patient taking pills will feel better, regardless of what the pills contain, simply because they believe the pills will work. Doctors studying the placebo effect have noticed that large pills work better than small pills, and that coloured pills work better than white ones.
Could the beneficial effects of homeopathy be entirely due to the placebo effect? If so, then homeopathy ought not to work on babies or animals, who have no knowledge that they are taking a medicine. Yet many people are convinced that it does.
Can science prove that homeopathy works?
In 1988, Jacques Benveniste was studying how allergies affected the body. He focussed on a type of blood cell known as a basophil, which activates when it comes into contact with a substance you're allergic to.
As part of his research, Benveniste experimented with very dilute solutions. To his surprise, his research showed that even when the allergic substance was diluted down to homeopathic quantities, it could still trigger a reaction in the basophils. Was this the scientific proof that homeopathic medicines could have a measurable effect on the body?
The memory of water
In an attempt to explain his results, Benveniste suggested a startling new theory. He proposed that water had the power to 'remember' substances that had been dissolved in it. This startling new idea would force scientists to rethink many fundamental ideas about how liquids behave.
Unsurprisingly, the scientific community greeted this idea with scepticism. The then editor of Nature, Sir John Maddox, agreed to publish Benveniste's paper - but on one condition. Benveniste must open his laboratory to a team of independent referees, who would evaluate his techniques.
Enter James Randi
When Maddox named his team, he took everyone by surprise. Included on the team was a man who was not a professional scientist: magician and paranormal investigator James Randi.
Randi and the team watched Benveniste's team repeat the experiment. They went to extraordinary lengths to ensure that none of the scientists involved knew which samples were the homeopathic solutions, and which ones were the controls - even taping the sample codes to the ceiling for the duration of the experiment. This time, Benveniste's results were inconclusive, and the scientific community remained unconvinced by Benveniste's memory of water theory.
Homeopathy undergoes more tests
Since the Benveniste case, more scientists have claimed to see measurable effects of homeopathic medicines. In one of the most convincing tests to date, Dr. David Reilly conducted clinical trials on patients suffering from hay fever. Using hundreds of patients, Reilly was able to show a noticeable improvement in patients taking a homeopathic remedy over those in the control group. Tests on different allergies produced similar results. Yet the scientific community called these results into question because they could not explain how the homeopathic medicines could have worked.
Then Professor Madeleine Ennis attended a conference in which a French researcher claimed to be able to show that water had a memory. Ennis was unimpressed - so the researcher challenged her to try the experiment for herself. When she did so, she was astonished to find that her results agreed.
Horizon takes up the challenge
Although many researchers now offered proof that the effects of homeopathy can be measured, none have yet applied for James Randi's million dollar prize. For the first time in the programme's history, Horizon decided to conduct their own scientific experiment.
The programme gathered a team of scientists from among the most respected institutes in the country. The Vice-President of the Royal Society, Professor John Enderby oversaw the experiment, and James Randi flew in from the United States to watch.
As with Benveniste's original experiment, Randi insisted that strict precautions be taken to ensure that none of the experimenters knew whether they were dealing with homeopathic solutions, or with pure water Two independent scientists performed tests to see whether their samples produced a biological effect. Only when the experiment was over was it revealed which samples were real.
To Randi's relief, the experiment was a total failure. The scientists were no better at deciding which samples were homeopathic than pure chance would have been.
Read more questions and answers about homeopathy.
Homeopathy: The Test
NARRATOR (NEIL PEARSON): This week Horizon is doing something completely different. For the first time we are conducting our own experiment. We are testing a form of medicine which could transform the world. Should the results be positive this man will have to give us $1m.
JAMES RANDI (Paranormal Investigator): Do the test, prove that it works and win a million dollars.
NARRATOR: But if the results are negative then millions of people, including some of the most famous and influential in the world, may have been wasting their money. The events that would lead to Horizon's million dollar challenge began with Professor Madeleine Ennis, a scientist who may have found the impossible.
PROF. MADELEINE ENNIS (Queen's University, Belfast): I was incredibly surprised and really had great feelings of disbelief.
NARRATOR: Her work concerns a type of medicine which defies the laws of science.
WALTER STEWART (Research Chemist): If Madeleine Ennis turns out to be right it means that science has missed a huge chunk of something.
NARRATOR: She has reawakened one of the most bitter controversies of recent years.
PROF. BOB PARK (University of Maryland): Madeleine Ennis's experiments cannot be right. I mean it's, they're, they're, preposterous.
MADELEINE ENNIS: I have no explanation for what happened. However, this is science. If we knew the answers to the questions we wouldn't bother doing the experiments.
NARRATOR: It's all about something you can find on every high street in Britain: homeopathy. Homeopathy isn't some wacky, fringe belief. It's over 200 years old and is used by millions of people, including Presidents and pop stars. It's even credited with helping David Beckham get over his foot injury and the Royals have been keen users since the days of Queen Victoria, but it's also a scientific puzzle. What makes it so mysterious is its two guiding principles, formulated in the 18th century. The first principle is that to find a cure you look for a substance that actually causes the symptoms you're suffering from. It's the principle that like cures like.
DR PETER FISHER (Homeopath to The Queen): For instance in colds and hay fever something we often use is allium cepa which is onion and of course we all know the effects of chopping an onion, you know the sore streaming eyes, streaming nose, sneezing and so we would use allium cepa, onion, for a cold with similar sorts of features.
NARRATOR: This theory that like cures like led to thousands of different substances being used, some of them truly bizarre.
DR LIONEL MILGROM (Homeopath): In principle you can make a homeopathic remedy out of absolutely anything that's plant.
PETER FISHER: Deadly nightshade.
LIONEL MILGROM: Animal.
PETER FISHER: Snake venom.
LIONEL MILGROM: Mineral.
PETER FISHER: Calcium carbonate, which is of course chalk.
LIONEL MILGROM: Disease product.
PETER FISHER: Tuberculous gland of a cow.
LIONEL MILGROM: Radiation.
NARRATOR: But then homeopaths found that many of these substances were poisonous, so they started to dilute them. This led to the extraordinary second principle of homeopathy: the more you dilute a remedy the more effective it becomes, provided it's done in a special way. The method homeopaths use to this day is called serial dilution. A drop of the original substance, whether it's snake venom or sulphuric acid, is added to 99 drops of waster or alcohol. Then the mixture is violently shaken. Here it's done by machine, but traditionally homeopaths would hit the tube against a hard surface. Either way, homeopaths believe this is a vital stage. It somehow transfers the healing powers from the original substance into the water itself. The result is a mixture diluted 100 times.
LIONEL MILGROM: That will give you what's called a 1C solution, that's one part in 100. You then take that 1C solution and dissolve it in another 99 parts and now you end up with a 2C solution.
NARRATOR: At 2C the medicine is one part in 10,000, but the homeopaths keep diluting and this is where the conflict with science begins. At 6C the medicine is diluted a million million times. This is equivalent to one drop in 20 swimming pools. Another six dilutions gives you 12C. This is equivalent to one drop in the Atlantic Ocean, but even this is not enough for most homeopathic medicines. The typical dilution is 30C, a truly astronomical level of dilution.
BOB PARK: One drop in all of the oceans on Earth would be much more concentrated than that. I would have to go off the planet to make that kind of dilution.
NARRATOR: But homeopaths believe that a drop of this ultra dilute solution placed onto sugar pills can cure you. That's why homeopathy is so controversial because science says that makes no sense whatsoever.
BOB PARK: There is a limit to how much we can dilute any substance. We can only dilute it down to the point that we have one molecule left. The next dilution we probably won't even have that one molecule.
WALTER STEWART: It's possible to go back and count how many molecules are present in a homeopathic dose and the astonishing answer is absolutely none. There's less than a chance in a million, less than a chance in a billion that there's a single molecule.
NARRATOR: A molecule is the smallest piece of a substance you can have, so for something to have any effect at all conventional science says you need one molecule of it at the very least.
WALTER STEWART: Science has through many, many different experiments shown that when a drug works it's always through the way the molecule interacts with the body and, so the discovery that there's no molecules means absolutely there's no effect.
NARRATOR: That's why science and homeopathy have been at war for over 100 years. The homeopaths say that their remedies have healing powers. Science says there's nothing but water. Then one scientist claimed the homeopaths were right after all. Jacques Benveniste was one of France's science superstars. He had a string of discoveries to his name and some believed he was on his way to earning a Nobel Prize.
DR JACQUES BENVENISTE (National Institute for Medical Research): I was considered as, well in French we have a word which says Nobel is nobelisable, which means we can have a Nobel Prize because I started from scratch the whole field of research. I was the head of a very large team, had a lot of money and so I was a very successful person.
NARRATOR: Benveniste was an expert in the field of allergy, in particular he was studying a type of blood cell involved in allergic reactions - the basophil. When basophils come into contact with something you're sensitive to they become activated causing the telltale symptoms. Benveniste had developed a test that could tell if a person was allergic to something or not. He added a kind of dye that only turns inactive basophils blue, so by counting the blue cells he could work out whether there had been a reaction, but then something utterly unexpected started to happen.
JACQUES BENVENISTE: A technician told me one day I don't understand because I have diluted a substance that is activating basophils to a point where it shouldn't work and it still works.
NARRATOR: The researcher had taken the chemical and added water, just like homeopaths do. The result should have been a solution so dilute it had absolutely no effect and yet, bizarrely, there was a reaction. The basophils had been activated. Benveniste knew this shouldn't have been possible.
JACQUES BENVENISTE: I remember saying to this, to her, this is water so it cannot work.
NARRATOR: Benveniste's team was baffled. They needed to find out what was going on, so they carried out hundreds of experiments and soon realised that they'd made an extraordinary discovery. It seemed that when a chemical was diluted to homeopathic levels the result was a special kind of water. It didn't behave like ordinary water, it acted like it still contained the original substance. It was as if the water was remembering the chemical it had once contained, so Benveniste called the phenomenon the 'memory of water'. At last here was scientific evidence that homeopathy could work. Benveniste knew this was a radical suggestion, but there was a way to get his results taken seriously. He had to get them published in a scientific journal.
JACQUES BENVENISTE: A result doesn't exist until it is admitted by the scientific community. It's like, like being a good opera singer but singing in your bathroom. That's fine, but it's not Scala, Milan or the Met, Met or the Opera at Paris, what-have-you.
NARRATOR: So he sent his work to the most prestigious journal in the world, a journal which for over 100 years has reported the greatest of scientific discoveries: Nature.
SIR JOHN MADDOX (Nature Editor 1980-1995): Nature is the place that everyone working in science recognises to be a way of getting publicity of the best kind.
NARRATOR: Benveniste's research ended up with one of the most powerful figures in science, the then Editor of Nature, Sir John Maddox. Maddox knew that the memory of water made no scientific sense, but he couldn't just ignore work from such a respected scientist, so he agonised about what to do. Eventually he reached a decision.
SIR JOHN MADDOX: I said OK, we'll publish your paper if you ;et us come and inspect your lab and he agreed, to my astonishment.
NARRATOR: So in June 1988 Benveniste's research appeared in the pages of Nature. It caused a scientific sensation. Benveniste became a celebrity. His memory of water made news across the world. He seemed to have found the evidence that made homeopathy scientifically credible, but the story wasn't quite over. Benveniste had agreed to let in a team from Nature. It was a decision he would live to regret. Maddox set about assembling his team of investigators and his choices revealed his true suspicions. First, he chose Walter Stewart, a scientist and fraud-buster, but his next choice would really cause a stir: James Randi.
JACQUES BENVENISTE: I looked in my books and I said who are, who is Randi and couldn't find any scientist called Randi.
NARRATOR: That was because the amazing Randi isn't a scientist, he's a magician, but he's no ordinary conjuror. He's also an arch sceptic, a fierce opponent of all things supernatural.
JACQUES BENVENISTE: I called John Maddox and I said what, what is this? I mean I thought you were coming with, with scientists to discuss science.
NARRATOR: But Randi felt he was just the man for the job. On one occasion he had fooled even experienced scientists with his spoon bending tricks.
JAMES RANDI: Scientists don't always think rationally and in a direct fashion. They're human beings like anyone else. They can fool themselves.
NARRATOR: So Randi became the second investigator.
JAMES RANDI: Astonishing.
NARRATOR: On 4th July 1988 the investigative team arrived in Paris ready for the final showdown.
SIR JOHN MADDOX: The first thing we did was to sit round the table in Benveniste's lab. Benveniste himself struck us all as looking very much like a film star.
JAMES RANDI: I found him to be a charming, very continental gentleman. He's a great personality. He was very much in control.
JACQUES BENVENISTE: We were quite relaxed because there was no reason why things should not go right.
NARRATOR: The first step was for Benveniste and his team to perform their experiment under Randi's watchful gaze. They had to prepare two sets of tubes containing homeopathic water and ordinary water. If the homeopathic water was having a real effect different from ordinary water then homeopathy would be vindicated. (ACTUALITY EXPERIMENT CHAT) As they plotted the results it was clear the experiment had worked.
JAMES RANDI: There were huge peaks coming up out of it and that was very active results, I mean very, very positive results.
WALTER STEWART: The astonishing thing about these results is that they repeated the claim, they demonstrated the claim that a homeopathic dilution, a dilution where there were no molecules, could actually have some sort of an effect.
NARRATOR: But Maddox had seen that the experimenters knew which tubes contained the homeopathic water and which contained the ordinary water, so perhaps unconsciously, this might have influenced the results, so he asked them to repeat the experiment. This time the tubes would be relabelled with a secret code so that no-one knew which tube was which.
JAMES RANDI: We went into a sealed room and we actually taped newspapers over the windows to the room that were accessible to the hall.
WALTER STEWART: We recorded in handwriting which tube was which and we put this into an envelope and sealed it so that nobody could open it or change it.
NARRATOR: At this point the investigation took a turn for the surreal as they went to extraordinary lengths to keep the code secret.
JAMES RANDI: Walter and I got up on the stepladder and stuck it to the ceiling of the lab.
WALTER STEWART: There it was taped above us as all of this work went on.
JACQUES BENVENISTE: Sticking an envelope to the ceiling was utterly ridiculous. There is no way you can associate that with science.
NARRATOR: With the codes out of reach the final experiment could begin. By now Benveniste had lost control of events.
JACQUES BENVENISTE: It was a madhouse. Randi was doing magician tricks.
JAMES RANDI: Yes I was doing perhaps a little bit of sleight-of-hand with an object or something like that, just to lighten the atmosphere.
NARRATOR: Soon the analysis was complete. It was time to break the code to see if the experiment had worked. Benveniste and his team were brimming with optimism.
JAMES RANDI: Oh my goodness it was party-time, cracked crabs legs and magnums, literally, of champagne packed in ice.
WALTER STEWART: We were going to be treated to a wonderful dinner. The press, many members of the press were there.
JAMES RANDI: John and Walter and I were looking at one another as if to say wow, if this doesn't work it's going to be a downer.
WALTER STEWART: Finally came the actual work of decoding the result.
JAMES RANDI: There was much excitement at the table. Everyone was gathered around.
NARRATOR: Benveniste felt sure that the results would support homeopathy and that he would be vindicated.
JAMES RANDI: That didn't happen. It was just a total failure.
SIR JOHN MADDOX: We said well nothing here is there?
WALTER STEWART: And immediately the mood in the laboratory switched, people burst into tears.
JAMES RANDI: It was general gloom.
NARRATOR: The team wrote a report accusing Benveniste of doing bad science and branding the claims for the memory of water a delusion. Benveniste's scientific reputation was ruined.
JACQUES BENVENISTE: Everybody believed that I am totally wrong. It's simply dismissed. Your phone call doesn't ring anymore. Just like actresses, or actress that have no, are no more in fashion the phone suddenly is silent.
NARRATOR: For now the memory of water was forgotten. Science declared homeopathy impossible once more, but strangely that didn't cause homeopathy to disappear. Instead it grew. Since the Benveniste affair sales of homeopathic medicines have rocketed. Homeopathy has become a trendy lifestyle choice, one of the caring, all natural medicines, more popular in the 21st-century than ever before. Despite the scepticism of science millions of people use it and believe it has helped them, like Marie Smith. Fifteen years ago Marie was diagnosed with a life-threatening blood disorder.
MARIE SMITH: I was more concerned for me children. I used to look at them thinking I may, may not be here one day for yous. That was the worst part of it.
NARRATOR: She'd tried everything that conventional medicine could offer, including drugs and surgery. Nothing seemed to work. Then she tried homeopathy. She took a remedy made from common salt.
MARIE SMITH: It's like somebody putting me in a coffin and taking me back out again. That's just the way I felt and the quality of my life changed completely.
NARRATOR: Since then Marie has been healthy and she has no doubt it's homeopathy that's helped her.
MARIE SMITH: I know it saved my life and it's made my life a lot different, yeah and I'm just glad I'm enjoying these grandchildren which I never thought I would do.
NARRATOR: There are thousands of cases like Marie's and they do present science with a problem. If homeopathy is scientific nonsense then why are so many people apparently being cured by it? The answer may lie in the strange and powerful placebo effect. The placebo effect is one of the most peculiar phenomena in all science. Doctors have long known that some patients can be cured with pills that contain no active ingredient at all, just plain sugar, what they call the placebo, and they've noticed an even great puzzle: that larger placebo pills work better than small ones, coloured pills work better than white pills. The key is simply believing that the pill will help you. This releases the powers in our minds that reduce stress and that alone can improve your health.
BOB PARK: Stress hormones make you feel terribly uncomfortable. The minute you relieve the anxiety, relieve the stress hormones people do feel better, but that's a true physiological effect.
NARRATOR: Scientists believe the mere act of taking a homeopathic remedy can make people feel better and homeopathy has other ways of reducing stress.
LIONEL MILGROM: And is there any particular time of day that you will, you'll, you'll have that feeling?
NARRATOR: A crucial part of homeopathic care is the consultation.
LIONEL MILGROM: The stress that you have at work, is that, are those around issues that make you feel quite emotional?
LIONEL MILGROM: The main thing about a homeopathic interview is that we do spend a lot of time talking and listening to the patient. We would ask questions of how they eat, how they sleep, how much worry and tension there is in their lives, hopefully give them some advice about how to actually ease problems of stress.
PATIENT I just feel I want to have something more natural.
LIONEL MILGROM: Yeah…
NARRATOR: So most scientists believe that when homeopathy works it must be because of the placebo effect.
BOB PARK: As far as I know it's the only thing that is really guaranteed to be a perfect placebo. There is no medicine in the medicine at all.
NARRATOR: It seems like a perfect explanation, except that homeopathy appears to work when a placebo shouldn't - when the patient doesn't even know they're taking a medicine. All over the country animals are being treated with homeopathic medicines. Pregnant cows are given dilute cuttlefish ink, sheep receive homeopathic silver to treat eye infections, piglets get sulphur to fatten them up. A growing number of vets believe it's the medicine of the future, like Mark Elliot who's used homeopathy his whole career, on all sorts of animals.
MARK ELLIOT (Homeopathic Vet): Primarily it's dogs and horses, but we also treat cats, small rodents, rabbits, guinea pigs, even reptiles, but I have treated an elephant with arthritis and I've heard of colleagues recently who treated giraffes. It works on any species exactly the same as in the human field.
NARRATOR: Mark made it his mission to prove that homeopathy works. He decided to study horses with cushing's, a disease caused by cancer. He treated them all with the same homeopathic remedy. The results were impressive.
MARK ELLIOT: We achieved an overall 80% success rate which is great because that is comparable with, with modern medical drugs.
NARRATOR: To Mark this was clear proof that homeopathy can't be the placebo effect.
MARK ELLIOT: You can't explain to this animal why the treatment it's being given is going to ben, to benefit it, or how it's potentially going to benefit it and as a result, when you see a positive result in a horse or a dog that to me is the ultimate proof that homeopathy is not placebo, homeopathy works.
NARRATOR: But Mark's small trial doesn't convince the sceptics. They need far more evidence before they'll believe that homeopathic medicines are anything more than plain water.
JAMES RANDI: I've heard it said that unusual claims require unusually good proof. That's true. For example, if I tell you that at my home in Florida in the United States I have a goat in my garden. You could easily check that out. Yeah, looks like a goat, smells like a goat, so the case is essentially proven, but if I say I have a unicorn, that's a different matter. That's an unusual claim.
NARRATOR: To scientists the claim that homeopathic water can cure you is as unlikely as finding a unicorn.
JAMES RANDI: Yes, there is a unicorn. That is called homeopathy.
NARRATOR: Homeopathy needed the very highest standards of proof. In science the best evidence there can be is a rigorous trial comparing a medicine against a placebo and in recent years such trials have been done with homeopathy. David Reilly is a conventionally trained doctor who became intrigued by the claims of the homeopaths. He wanted to put homeopathy to the test and decided to look at hay fever. Both homeopathy and conventional medicine use pollen as a treatment for hay fever. What's different about homeopathy is the dilution.
DR DAVID REILLY (Glasgow Homeopathic Hospital): The single controversial element is that preparing this pollen by the homeopathic method takes it to a point that there's not a single molecule of the starting material present. I confidently assumed that these diluted medicines were placebos.
NARRATOR: David Reilly recruited 35 patients with hayfever. Half of them were given a homeopathic medicine made from pollen, half were given placebo, just sugar pills. No one knew which was which. For four weeks they filled in a diary measuring how bad their symptoms were. The question was: would there be a difference?
DAVID REILLY: To our collective shock a result came out that was very clear those on the active medication had a substantially greater reduction in symptoms than those receiving the placebo medicine. According to that data the medicine worked.
NARRATOR: But to be absolutely rigorous Reilly decided to repeat the study and he got the same result. Then he went further and tested a different type of allergy. Again the result was positive, but despite all these studies, most scientists refuse to believe his research.
DAVID REILLY: It became obvious that in certain minds 100 studies, 200 studies would not change the mental framework and so I'm sceptical that if 200 haven't changed it I don't think 400 would change it.
NARRATOR: The reason Reilly's research was dismissed was because his conclusion had no scientific explanation. Sceptics pointed to the glaring problem: there was still no evidence as to how something that was pure water could actually work.
BOB PARK: If you design a medication to take advantage of what we know about physiology we're not surprised when it works. When, when you come up with no explanation at all for how it could work and then claim is works we're not likely to take it seriously.
NARRATOR: To convince science, homeopathy had to find a mechanism, something that could explain how homeopathic water could cure you. That meant proving that water really does have a memory. Then a scientist appeared to find that proof. Madeleine Ennis has never had much time for homeopathy. As a professor of pharmacology she knows its scientifically impossible.
MADELEINE ENNIS: I'm a completely conventional scientist. I have had no experience of using non-conventional medications and have no intention really of starting to use them.
NARRATOR: But at a conference Ennis heard a French scientist present some puzzling results, results that seemed to show that water has a memory.
MADELEINE ENNIS: Many of us were incredibly sceptical about the findings. We told him that something must have gone wrong in the experiments and that we didn't believe what he had presented.
NARRATOR: He replied with a challenge.
MADELEINE ENNIS: I was asked whether, if I really believed my viewpoint, would I test the hypothesis that the data were wrong?
NARRATOR: Ennis knew that the memory of water breaks the laws the science, but she believed that a scientist should always be willing to investigate new ideas, so the sceptical Ennis ended up testing the central claim of homeopathy. She performed an experiment almost identical to Benveniste's using the same kind of blood cell. Then she added a chemical, histamine, which had been diluted down to homeopathic levels. The crucial question: would it have any effect on the cells? To find out she had to count the cells one by one to see whether they had been affected by the homeopathic water. The results were mystifying. the homeopathic water couldn't have had a single molecule of histamine, yet it still had an effect on the cells.
MADELEINE ENNIS: They certainly weren't the results that I wanted to see and they definitely weren't the results that I would have liked to have seen.
NARRATOR: Ennis wondered whether counting by hand had introduced an error, so she repeated the experiment using an automated system to count the cells, and astonishingly, the result was still positive.
MADELEINE ENNIS: I was incredibly surprised and really had great feelings of disbelief, but I know how the experiments were performed and I couldn't see an error in what we had done.
NARRATOR: These results seemed to prove that water does have a memory after all. It's exactly what the homeopaths have been hoping for.
PETER FISHER: If these results become generally accepted it will revolutionise the view of homeopathy. Homeopathy will suddenly become this idea that was perhaps born before its time.
LIONEL MILGROM: It's particularly exciting because it does seem to suggest that Benveniste was correct.
NARRATOR: At last here is evidence from a highly respected researcher that homeopathic water has a real biological effect. The claims of homeopathy might be true after all. However, the arch sceptic Randi is unimpressed.
JAMES RANDI: There is so many ways that errors are purposeful interference can take place.
NARRATOR: As part of his campaign to test bizarre claims Randi has decided to put his money where his mouth is. On his website is a public promise: to anyone who prove the scientifically impossible Randi will pay $1m.
JAMES RANDI: This is not a cheap theatrical stung. It's theatrical, yes, but it's a million dollar's worth.
NARRATOR: Proving the memory of water would certainly qualify for the million dollars. To win the prize someone would simply have to repeat Ennis's experiments under controlled conditions, yet no-one has applied.
JAMES RANDI: Where are the homeopathic labs, the biological labs around the world, who say that this is the real thing who would want to make a million dollars and aren't doing it?
NARRATOR: So Horizon decided to take up Randi's challenge. We gathered experts from some of Britain's leading scientific institutions to help us repeat Ennis's experiments. Under the most rigorous of conditions they'll see whether they can find any evidence for the memory of water. We brought James Randi over from the United States to witness the experiment and we came to the world's most august scientific institution, the Royal Society. The Vice-President of the Society, Professor John Enderby, agreed to oversee the experiment for us.
PROF. JOHN ENDERBY: ...but they'll, of course as far as the experimenters are concerned they'll have totally different numbers…
NARRATOR: And with a million dollars at stake James Randi wants to make sure there's no room for error.
JAMES RANDI: ...keeping the original samples, so I'm very happy with that provision. I'm willing to accept a positive result for homeopathy or for astrology or for anything else. I may not like it, but I have to be willing to accept it.
NARRATOR: The first stage is to prepare the homeopathic dilutions. We came to the laboratories of University College London where Professor Peter Mobbs agreed to produce them for us. He's going to make a homeopathic solution of histamine by repeatedly diluting one drop of solution into 99 drops of water.
PETER MOBBS: OK, now I'm transferring the histamine into 9.9mmls of distilled water and then we'll discard the tip.
NARRATOR: For comparison we also need control tubes, tubes that have never had histamine in them. For these Peter starts with plain water.
PETER MOBBS: In it goes.
NARRATOR: This stage dilutes the solutions down to one in 100 - that's 1C. We now have 10 tubes. Half are just water diluted with more water, the control tubes, half are histamine diluted in water. These are all shaken, the crucial homeopathic step. Now he dilutes each of the tubes again, to 2C. Then to 3C, all the way to 5C.
PETER MOBBS: The histamine's now been diluted ten thousand million times. Still a few molecules left in there, but not very many.
NARRATOR: Then we asked Professor of Electrical Engineering, Hugh Griffiths, to randomly relabel each of our 10 tubes. Now only he has the code for which tubes contain the homeopathic dilutions and which tubes contain water.
HUGH GRIFFITHS: OK, so there's the record of which is which. I'm going to encase it in aluminium foil and then seal it in this envelope here.
NARRATOR: Next the time-consuming task of taking these solutions down to true homeopathic levels. UCL scientist Rachel Pearson takes each of the tubes and dilutes them down further - to 6C. That's one drop in 20 swimming pools. To 12C - a drop in the Atlantic. Then to 15C - one drop in all the world's oceans. The tubes have now been diluted one million million million million million times. Some are taken even further down, to 18C. Every tube, whether it contains histamine or water, goes through exactly the same procedure. To guard against any possibility of fraud, Professor Enderby himself recodes every single tube. The result is 40 tubes none of which should contain any molecules of histamine at all. Conventional science says they are all identical, but if Madeleine Ennis is right her methods should tell which ones contain the real homeopathic dilutions. Now we repeat Ennis's procedure. We take a drop of water from each of the tubes and add a sample of living human cells. Then it's time for Wayne Turnbull at Guys Hospital, to analyse the cells to see whether the homeopathic water has had any effect. He'll be using the most sophisticated system available: a flow cytometer.
WAYNE TURNBULL: Loading it up, bringing it up to pressure. Essentially the technology allows us to take individual cells and push them past a focused laser beam. A single stream of cells will be pushed along through the nozzle head and come straight down through the machine. The laser lights will be focussed at each individual cell as it goes past. Reflected laser light is then being picked up by these electronic detectors here.
NARRATOR: By measuring the light reflected off each cell the computer can tell whether they've reacted or not.
WAYNE TURNBULL: This is actually a very fast machine. I can run up to 100 million cells an hour.
JAMES RANDI: Whoa.
NARRATOR: But to be absolutely rigorous we asked a second scientist, Marian Macey at the Royal London Hospital, to perform the analysis in parallel. Our two labs get to work. Using a flow cytometer they measure how many of the cells are being activated by the different test solutions. Some tubes do seem to be having more of an effect than others. The question is: are they the homeopathic ones? At last the analysis is complete. We gather all the participants here to the Royal Society to find out the results. First, everyone confirms that the experiment has been conducted in a rigorous fashion.
MARION MACEY: I applied my own numbering system to the…
RACHEL PEARSON: ...5, 5.4 millimolar solution…
WAYNE TURNBULL: ...we eventually did arrive at a protocol that we were happy with.
NARRATOR: Then there's the small matter of the million dollars.
JOHN ENDERBY: James, is the cheque in your pocket ready now?
JAMES RANDI: We don't actually carry a cheque around. It's in the form of negotiable bonds which will be immediately sep, separated from our account and given to whoever should win the prize.
NARRATOR: We asked the firm to fax us confirmation that the million dollar prize is there.
JOHN ENDERBY: OK, now look, I'm going to open this envelope.
NARRATOR: Now at last it's time to break the code. On hand to analyse the results is statistician Martin Bland.
JOHN ENDERBY: 59.
NARRATOR: We've divided the tubes into those that did and didn't seem to have an effect in our experiment.
JOHN ENDERBY: 62.
NARRATOR: Each tube is either a D for the homeopathic dilutions, or a C, for the plain water controls.
JOHN ENDERBY: 52 and 75 were Cs.
NARRATOR: Rachel Pearson identifies the tubes with a C or D. If the memory of water is real each column should either have mostly Cs or mostly Ds. This would show that the homeopathic dilutions are having a real effect, different from ordinary water. There's a hint that the letters are starting to line up.
JOHN ENDERBY: Column 1 we've got 5 Cs and a D. Column 3 we've got 4 Cs and a D, so let's press on. 148 and 9, 28 and…
NARRATOR: But as more codes are read out the true result becomes clear: the Cs and Ds are completely mixed up. The results are just what you'd expect by chance. A statistical analysis confirms it. The homeopathic water hasn't had any effect.
PROF. MARTIN BLAND (St. George's Hospital Medical School): There's absolutely no evidence at all to say that there is any difference between the solution that started off as pure water and the solution that started off with the histamine.
JOHN ENDERBY: What this has convinced me is that water does not have a memory.
NARRATOR: So Horizon hasn't won the million dollars. It's another triumph for James Randi. His reputation and his money are safe, but even he admits this may not be the final word.
JAMES RANDI: Further investigation needs to be done. This may sound a little strange coming from me, but if there is any possibility that there's a reality here I want to know about it, all of humanity wants to know about it.
NARRATOR: Homeopathy is back where it started without any credible scientific explanation. That won't stop millions of people putting their faith in it, but science is confident. Homeopathy is impossible.