Part of the skepticism many doctors still feel about yohimbine may stem from studies published in the late 1960s and early 1970s that claimed amazing success rates in treating impotent men with yohimbine. One research team reported that in a study of 1 0,000 men with erection problems, up to 80 percent reported "good to excellent" results while taking the drug. Another study reported that, measured in terms of erections and/or orgasms, yohimbine was up to five times as effective as a placebo.

The trouble was, it turned out that the "miracle cure" used in the studies was a drug called Afrodex. This drug was not pure yohimbine but a whole witch's brew of stuff-yohimbine, plus methyl testosterone, plus nux vomica, the plant source of the powerful poison strychnine. More careful review of these studies revealed some dubious statistics-and some suggestion that the drug itself might be toxic. The Food and Drug Administration removed Afrodex from the market in 1973. (Impotence, after all, is better than death.)