I used to think homeopathy was helpful. Now I’m a critic. So what happened?

    3 May 2016

    As a young doctor, almost 40 years ago, I worked for several months in a homeopathic hospital. This experience impressed me, and I was not far from believing that homeopathy might be a valuable form of healthcare. Today, I am an outspoken critic of homeopathy. How come?

    Most people who know about this change of mind assume that, at some time, there must have been some kind of Pauline conversion, ie a key event that opened my eyes and abruptly changed my view. However, this never happened. The truth is more complex, and my change of mind occurred gradually. Looking back, I recognise five distinct stages.

    Homeopathy might work
    As a boy, I had been treated regularly by our family doctor who happened to be a prominent homeopath. Later, as a medical student, I learnt very little about homeopathy. All I remember is that my pharmacology professor had tantrums each time the ‘h-word’ was mentioned. Therefore, I did not think all that highly of the subject when I first entered the only homeopathic hospital of Germany to work as a junior doctor. To my surprise, however, I soon took a liking to this way of treating patients. It would be wrong to deny it: I was impressed with what I saw.

    The hospital was well run, the nurses were very caring, our boss was very much, almost despotically, in charge, and my colleagues were truly helpful in helping me find my feet. Ask any doctor about his or her first real exposure to patients and you are likely to hear a similar story regardless of where they happened to make their first steps in. At that stage, a novice clinician has studied for six years and is frantically excited to put all this knowledge into practice. At the same time, one is petrified about making a mistake. In this atmosphere, it is only natural to be easily impressed.

    Once I had grasped the basics of homeopathy, I began to prescribe remedies which, according to my knowledge of pharmacology, could not possibly have any effect. After all, they typically contained not a single molecule of an active substance. Yet, in total defiance of pharmacology, my patients seemed to benefit from taking them. How could this be?

    I gradually realised that patients and their responses were more complex than I had imagined. There were, of course, several possible explanations for the clinical improvement of our patients. I considered the placebo effect, and my boss alerted me to another factor: we regularly discontinued the useless and often harmful drugs which our patients had previously been prescribed. These factors might be contributors, I reckoned, but the notion that our homeopathic remedies were working could not be totally rejected either. In a word, I thought homeopathy might work.

    Homeopathy is worthy of further study
    After a few months in this hospital, I moved on and eventually became an almost entirely conventional physician. I say ‘almost’ because my time in the homeopathic hospital did convince me of the need to solve one riddle: why precisely do patients benefit from taking homeopathic remedies?

    Meanwhile, I had been infected with the ‘science bug’. I had worked several years in basic research and had begun to think more critically and analyse things systematically. In medical school, we had simply no time for that; we all struggled to take in the huge amount of knowledge presented to us. Critical thinking had never been on the agenda.

    Eventually, I did a PhD and, for about a decade, I conducted medical research in parallel to looking after patients. This was both enjoyable and successful. I was appointed as a professor first at Hannover and then at Vienna.

    Whenever the occasion arose to rekindle my interest in alternative medicine, I took this chance. Alternative medicine had become a hobby horse of mine, and I felt that this area was a rich field for exciting research. This sideline turned out to be so successful that I decided to risk another career change and accept a post as professor of complementary medicine at Exeter.

    This meant farewell to being a clinician; now I was a full-time researcher into homeopathy and other alternative therapies. I recruited a team of about 20 scientists with all sorts of professional backgrounds, and together we conducted clinical trials and systematic reviews of studies done previously on various aspects of alternative medicine, including of course homeopathy.

    Homeopathy is a placebo therapy
    As our investigations progressed, the possibility that homeopathy might be more than a placebo therapy became more and more remote. Initially the results were mixed but, as time went by, the most rigorous studies and reviews demonstrated more and more clearly that highly diluted homeopathic remedies had no effect beyond placebo. This is perhaps best reflected in the conclusions of the articles we published on the subject; they went from a neutral to an outspoken critical stance.

    After two decades of research, it had finally become undeniably clear that highly diluted homeopathic remedies are pure placebos. In a way, this finding was a disappointment to me; I would have been delighted if the evidence had led me in the opposite direction. Anyone who proves the basic assumptions of homeopaths to be correct simultaneously disproves entire chapters of the textbooks of physics, chemistry and pharmacology and therefore deserves at least one Nobel prize.

    Homeopathy can be dangerous
    One argument that I often hear when presenting my findings is that ‘at least homeopathy cannot do any harm’. At first sight, it sounds convincing; however, on reflection one has to doubt its validity. Highly diluted homeopathic remedies certainly lack any active principle, and therefore they ought to be harmless. But can that also be said of homeopathy as a whole?

    One of our investigations demonstrated quite clearly that homeopaths might be inflicting considerable harm through issuing wrong advice to their patients. We had shown that many UK homeopaths recommended to parents not to vaccinate their children. Instead, they advised them to use ‘homeopathic vaccinations’, or homeoprophylaxis, as they like to call it, for which there is not a shred of evidence. The phenomenon of homeopaths discouraging parents from vaccinating their kids is now well studied and has been confirmed in many parts of the world. It means that homeopaths endanger the herd immunity of entire populations which might bring back epidemics that we had long considered a thing of the past.

    More generally, this type of research brought the realisation that homeopathy carries a real and significant risk: whenever it is used to replace an effective intervention for a serious condition, it can become a risk to life.

    Consumers need to be warned
    Homeopathy differs from conventional medicine in many ways. One of them is the fact that patients often use it without consulting any healthcare professionals. This means that, contrary to mainstream medicine, one ought to address consumers directly and provide them with reliable, factual information. Medical researchers tend to publish their results in learned journals which are read by professionals who, in turn, advise their patients accordingly. For many years, this is also what I did with our findings regarding homeopathy and other alternative therapies.

    But such procedures fail to reach the real target. If I publish about the ineffectiveness or risks of homeopathy in the BMJ, for instance, my paper might interest some doctors but it will hardly reach the consumer, ie the person who makes the decision to use homeopathy for his or her illness. To reach the public, it is necessary to write in newspapers and blogs. I felt that not to take this last step would have meant not fulfilling my moral and ethical duty as a physician and scientist.

    I took this decision several years ago. Ever since I have been busy trying to provide responsible information about alternative medicine to the general public. It is no task that brings me money or friends; in fact, it is a quick way to make plenty of (sometimes powerful) enemies. Yet it is a task that has the potential to do an immense amount of good. And that’s why I do it.

    Edzard Ernst, emeritus professor at the University of Exeter, is the author of A Scientist in Wonderland and the awardee of the John Maddox Prize 2015 for standing up for science. He blogs at