Okay, now look. There's nothing wrong with the idea of homeopaths giving out what amount to sugar pills. The placebo effect can be powerful, because it's not just about the pill, it's about the cultural meaning of the treatment. So we know from research that four placebo sugar pills a day are more effective than two for eradicating gastric ulcers (and that's not subjective - you measure ulcers by putting a camera into your stomach); we know that salt water injections are a more effective treatment for pain than sugar pills, not because salt water injections are medically active, but because injections are a more dramatic intervention. Similarly, we know that sugar pills have no physical side effects. This is great, because there are many people for whom there is little effective biomedical treatment: a lot of back pain, for example, or most colds and flu. Trying every pill in the book will only elicit side effects, so a sugar pill might be a great remedy.

Homeopaths would be fine, if they could just shut up about serious stuff, like Aids, or malaria, or MMR.

This week I received a flyer for a conference organised by the Society of Homeopaths, the biggest professional organisation for homeopaths in the UK. "Join us at this one-day symposium in London for a fascinating insight into the role of homeopathy in treating HIV/Aids." It's a pretty fascinating flyer. "In searching for an effective remedy for treating the Aids epidemic in Africa, the UK homeopath Peter Chappell discovered a method to design remedies fitting the totality of a disease. These remedies are now known as PC remedies." In case you're wondering how he makes them, Peter explains on his own site how he "creates a holistic mirror energy/information set to the disease using a special process he does not yet disclose".

The society's conference materials are gushing. "He [their lecturer] observed that in just a few days or weeks patients become symptom-free and able to return to their jobs and schools or to look after their children again. Peter believes that using the PC1 remedy, the Aids epidemic can be called to a halt, and that homeopaths are the ones that can do it." On his own site, Peter is even more explicit: "PC1 for HIV/Aids works". How well? "In all cases."

Placebos are great, but when their right to peddle fiction is flattered too hard, people can get carried away, and homeopathy has a bad history in this regard.

A Newsnight undercover survey caught out 10 who were cheerfully recommending people to use ineffective homeopathic malaria prophylaxis when travelling to high-risk areas, giving no sensible advice to accompany it. A published undercover survey, with a researcher posing as a mother asking for vaccine advice, polled 77 homeopaths: not one advised her to give MMR to her child, and a third actively advised against it.

Peddling fiction is the homeopath's trade. Attacking medicine is their marketing device. It's probably harmless, and arguably helpful, but only if you are absolutely certain that you can manage those two risks. I see no sign of critical self-appraisal within the profession.

Full references and flyer: badscience.net