Why do so many otherwise intelligent patients and therapists pay considerable sums for products and therapies of alternative medicine, even though most of these either are known to be useless or dangerous or have not been subjected to rigorous scientific testing? The author proposes a number of reasons this occurs: (1) Social and cultural reasons (e.g., many citizens' inability to make an informed choice about a health care product; anti-scientific attitudes meshed with New Age mysticism; vigorous marketing and extravagant claims; dislike of the delivery of scientific biomedicine; belief in the superiority of "natural" products); (2) psychological reasons (e.g., the will to believe; logical errors of judgment; wishful thinking, and "demand characteristics"); (3) the illusion that an ineffective therapy works, when actually other factors were at work (e.g., the natural course or cyclic nature of the disease; the placebo effect; spontaneous remission; misdiagnosis). The author concludes by acknowledging that when people become sick, any promise of a cure is beguiling. But he cautions potential clients of alternative treatments to be suspicious if those treatments are not supported by reliable scientific research (criteria are listed), if the "evidence" for a treatment's worth consists of anecdotes, testimonials, or self-published literature, and if the practitioner has a pseudoscientific or conspiracy-laden approach, or promotes cures that sound "too good to be true."