Homeopathy
An extremely tentative summary of homeopathic principles from the NIH's National Center for Complementary and Alternative Medicine.
YouTube video about Jacques Benveniste's homeopathy research. He comes across as a careful, reasonable person.
Meta-analyses of homeopathy from Linde in the Lancet (1997) and reappraised in the Journal of Clinical Epidemiology (1999), and from Shang in the Lancet (2005)
Concerning the Shang article, see the Lancet editorial and commentary. There are many rebuttals (here, here, and here) and a rebuttal to the rebuttals. This one, from an alternative medicine advocate, is not the most convincing but it certainly is dramatic.
Since I badmouthed the Boiron homeopathic flu remedy Oscillococcinum, here's a study of its effectiveness. (Bonus: Boiron has a children's version of Oscillococcinum with exactly the same ingredients at the same concentration. Maybe the children's version has a different flavor?) Boiron is actually pretty responsible as homeopaths go (they don't claim to cure cancer, for instance), but the British Society of Homeopaths is exploring homeopathic treatment for AIDS, including treatment by MP3. After a media sting caught British homeopaths advocated nosode-based malaria prophylactics, WHO officially advised against using homeopathy to prevent malaria.
And just for fun (and in honor of the 10th anniversary of its fall) here are some clinical cases treated with 30C dilutions of the Berlin Wall.
Placebo effect
A review of the nature and mechanism of the placebo effect. The initial pages are heavy going unless you've taken some neuroscience, but I found the portion "Placebo Responses in Clinical Trials" more accessible. Also discusses the nocebo effect. Based on how complicated it is, you can understand why it's difficult to control for the placebo effect.
A critique of slavish adherence to randomized clinical trials versus placebo, in response to this commentary in Newsweek.
A NYT article about an over-the-counter (of course) children's placebo.
A major part of the confusion over alternative treatments is their inexplicable effectiveness in cases that are medically hopeless. (Of course, we don't hear about people whose alternative treatments failed) In the case of cancer, spontaneous remission can and does occur, though only recently has mainstream medicine tried to measure how often and under what circumstances it happens. Probably the most spectacular cures attributed to alternative medicine come from events like these.
Acupuncture
The Cochrane Collaboration (a group that monitors medical literature for evidence of treatment effectiveness and performs periodic meta-analyses) has hundreds of acupuncture effectiveness reviews. They all seem to say that evidence is lacking, of poor quality, or ambiguous. The National Center for Complementary and Alternative Medicine (NCCAM) has a section devoted to acupuncture, including acupuncture for a (small) set of particular conditions, such as for chronic lower back pain; you can decide for yourself whether it proves or disproves the effectiveness of acupuncture for back pain.
There is lots of acupuncture available locally. Here's a typical provider who proposes to treat conditions ranging from back pain and colds to angina and diabetes with acupuncture, based on the WHO's imprimatur. I wouldn't recommend treating a heart condition with acupuncture.
Radium tonics
There was a short-lived fad for everything Radium-laced in the 1920's, shortly after Radium was discovered but before it became clear it caused agonizing death due to bone cancer. This site is in French, but you can scroll through the horrific product ads. Radium (or, more commonly, Radon, which is a radioactive product of Radium decay) is still marketed as a health cure today; promoted, ironically, by an outfit called "Radiation, Science, and Health" which seems to conflate the notions that low doses of radiation may be harmless (quite possibly true) with the notion that radiation exposure has health benefits (false, as far as I know).
This 10' short from 1937 acknowledges the risks of radium exposure but still claims it has many health benefits; it seems to refer to both cancer treatment (plausible) and more general healing powers like treating wounds (no). The film says much more about societal attitudes than about radium itself, though it was considered a film about science at the time it was made. Before you dismiss it: it was nominated for an Oscar in 1938.
Chiropracty
The official list of treatable conditions from the American Chiropractic Association is relatively responsible (mostly musculoskeletal problems), but note the final sentence that adds "allergies, asthma, digestive disorders, otitis media (non-suppurative)" and the catch-all "and other disorders as new research is developed".
The National Center for Complementary and Alternative Medicine (NCCAM) is noncommittal on chiropracty, as with most treatments.
A typical meta-analysis (though only based on three trials) showing chiropracty does not help with infant colic, and a generally critical overall assessment of chiropracty, though with the exception of the treatment of lower back pain, where chiropracty seems slighly superior to standard interventions.
Herbal Medicine and Dietary Supplements
Most herbal medicines slip under the "Dietary Supplement" regulatory framework, so they receive significantly less scrutiny than normal drugs. This is probably because people think of them like vitamins, which are (mostly) pretty safe, except for iron. But herbal medicines can be powerfully active; see this JAMA editorial about ephedra and its summary:
If dietary supplements have or promote ... biological activity, they should be considered to be active drugs. ... Manufacturers of dietary supplements are trying to have it both ways. They claim their products are powerfully beneficial, on the one hand, but harmless on the other. To claim both makes no sense, and to claim either without trials demonstrating efficacy and safety is deceptive.
There is an NIH Office of Dietary Supplements; this is perhaps necessary because the FDA's ability to regulate dietary supplements is limited to wagging its finger and asking people to fill out forms. (See the pitiful FDA response to the question "Where can I get information about a dietary supplement?" and contrast it with the one at the NIH.)
There isn't much evidence that megavitamin therapy is particularly helpful. A lot of "common knowledge" has little clinical support, like taking vitamin C for colds.
Topical
Because they came up in class:
Placebos can have an effect on sports performance.
Apparently an E-meter is just a fancy Wheatstone Bridge. Look it up in the electricity and magnetism section of any physics textbook if you haven't encountered it before.
There are three synthetic cannabinoids that are available commercially in the US/Canada, but they are apparently quite expensive. According to this analysis, synthetic cannabinoids seem pretty effective, particularly in reducing chemotherapy-induced vomiting. I am surprised that medical marijuana advocates don't seem to mention these products, though I admit I'm not following this issue particularly closely. This earlier study evaluates smoked marijuana as well as synthetic versions: it seems pessimistic about anti-emesis but cautiously optimistic about appetite stimulation; note that this conclusion applies only to anorexia from AIDS and chemotherapy: it particularly excludes anorexia nervosa with its more complicated psychological issues.