But the study of the chemistry of medicinal plants did not begin until the 19th century. The active ingredients of many pharmaceuticals in widespread use today are identical to, or derivatives of, bioactive constituents of historic folk remedies. Indeed, Hippocrates reportedly prescribed willow bark and leaves for fever and the pain of childbirth. And in many cultures soaked willow leaves have been used as a topical painkiller. Moreover, salicylic acid is more irritating to the stomach than is aspirin.
Manmade drugs are often safer, as well as more effective, than their botanical correspondents.
But therapeutic successes with botanicals came at great human cost. The indications for using a given botanical were ill defined, dosage was arbitrary because the concentrations of the active ingredient were unknown, and all manner of contaminants were often present. More important, many of the remedies simply did not work, and some were harmful or even deadly. The only way to separate the beneficial from the useless or hazardous was through anecdotes relayed mainly by word of mouth. Other aspects of alternative medicine include pop psychology and the overlapping fields of paraphysics and parapsychology.