NEVER say that America's National Institutes of Health (NIH) has a closed mind. At the beginning of November, it organised a conference to investigate the usefulness of acupuncture—one of the most persistent and seemingly successful practices of so-called alternative medicine. And, perhaps to its own surprise, the panel of independent experts convened by the NIH to observe the conference and make a recommendation on policy towards acupuncture ended up supporting the use of needles for a diverse range of conditions.

At the top of the panel's list were nausea and vomiting—not the sort brought on by a heavy night out, but the more serious symptoms suffered by people undergoing chemotherapy for cancer, and also by many women in the early stages of pregnancy. The empanelled experts were also enthusiastic about the use of acupuncture for relieving pain. And they reviewed, with varying levels of enthusiasm, evidence that it can regulate the immune system, improve the outlook for patients suffering from chronic digestive disorders and menstrual cramps, and help to treat neurological complaints as varied as cerebral palsy, carpal-tunnel syndrome and the disabilities caused by strokes.

Acupuncture suffers from two barriers to more widespread acceptance by doctors. First, if it works, no one has any clear idea how—particularly given the wide range of ailments it is supposed to ameliorate. Second, it is difficult to do proper clinical trials to determine if it actually does work. Besides being expensive ($500,000 will just about buy you one), such trials demand what is known as a placebo control. This is a dummy treatment of no formal therapeutic value that allows researchers to discount the placebo effect—an improvement in a patient's condition brought about by the mere act of treating him.

Drugs are easy to substitute with placebos (a sugary pill is often sufficient), but it is difficult to replicate being skewered with needles. Also, the doctors involved in a trial are not supposed to know who is getting the treatment and who the placebo. Even if it proves possible to hoodwink a patient, perhaps by giving him a pointless pill and not mentioning that the real treatment under test is acupuncture, the doctor inserting the needles cannot be fooled.

As to how acupuncture works, the original Chinese explanation of “meridians” connecting different parts of the body is not widely accepted in the West. Instead, many researchers think that the relief the treatment appears to bring is just one big placebo effect.

Daniel Moerman, an anthropologist on the panel who has been a student of the placebo effect for 20 years, says his guess is that acupuncture does indeed exert a very powerful placebo effect but that it has real biological effects as well. There is now some evidence that he is right.

One measurable biological effect, the conference heard, is that the needling of particular points on the skin which acupuncturists use to relieve pain causes the brain to release natural opiates, known as endorphins. These are known to suppress pain. The idea that the analgesic effect of acupuncture is caused by endorphins is also supported by the fact that such pain relief is blocked when a patient is given naloxone, an antidote to morphine.

Getting round the problem of designing effective trials, though, is difficult, and there was a certain amount of handwaving about the distinction between the “efficacy” of a treatment, as proved formally in a trial, and its “effectiveness”, as observed in the cut and thrust of everyday medical practice. But, while it is true that many commonplace medical procedures have not themselves been subjected to formal trials, and are accepted because they are “effective” not “efficacious”, they are not the ones having to fight for recognition.

With that recognition now better established, more rigorous research is needed into the question of exactly which disorders acupuncture can help to treat. And nailing down a mechanism would certainly help the scientifically trained doctors of the West to accept it as valuable. Though the needle has not yet been located in the haystack, there is reason to believe that the search may be worthwhile.