Gerson therapy is a treatment regimen of which it is claimed that it is able to cure even severe cases of cancer through a special diet, coffee enemas, and various supplements. It does, of course, not cure cancer, but Charlotte Gerson – the current main promoter – has anecdotes! The treatments is named after the German crank Max Gerson. Charlotte is his daughter.
In 1977, Charlotte Gerson co-founded the Gerson Institute, which oversees The Baja Nutri Care Clinic in Tijuana, Mexico. Yup. It is illegal for a clinic to offer the Gerson treatment as a cancer cure in the U.S., for obvious reasons – it does not cure cancer, for instance, and it is rather dangerous (the Wikipedia article is actually decent). Charlotte Gerson is not a medical doctor, of course, but trains people in the Gerson method, lectures on the alleged benefits of the therapy and the conspiracy of evil forces trying to suppress her. She has written plenty of leaflets containing anecdotes and testimonials, but has done no studies and evidently doesn’t quite realize why anecdotes are not evidence and why real, controlled studies would be needed. She has also written a book on the Gerson therapy (with her son Howard Strauss, who also wrote a biography of old Max).
The appeal of the Gerson therapy is primarily a matter of fallacious appeals to nature (cancer is allegedly caused by “toxins”; also here), and Max Gerson managed to obtain the approval of several celebrities of his time (today the therapy is at least notably backed by some notorious moron called Charles). As with most crackpot treatments Gerson was also careful not to do any controlled studies but instead apply selection bias and rely on subjective validation, which is great, since in the case of alleged cancer treatments the failures won’t be widely advertised insofar as those patients won’t usually be there to provide critical testimonials (see also this). The Gerson therapy is covered in detail here.
Stay away from Steve Kroschel’s ghastly conspiracy theory pseudo-documentary commercial for the therapy called “The beautiful truth”. The movie is pretty much an altmed version of Expelled, and the collection of fallacies, distortions, and conspiracy mongering would be hilarious were its potential impact not so frightening. It is discussed here and here, and here. In order to make sure his idiocy is sufficiently garishly displayed Kroschel throws in plenty of other crackpottery as well. It is nevertheless endorsed, apparently, by Charlotte Gerson, Howard Strauss and the Gerson Institutes’s executive director Anita Wilson.
The Gerson therapy is a repertoire mainstay at quackwatch.
Diagnosis: Completely delusional crackpot, exhibiting such ignorance of science and evidence, and insulation to truth and reality that it shocks even hardened loon investigators. The Gerson therapy is sufficiently popular for Charlotte Gerson to be deemed extremely dangerous.