Throughout history, humans have taken substances other than food into their bodies in ways that usually were socially accepted. The most common form has been as medicine, in attempts to change some feeling of ill-being or disease, such as PAIN, fatigue, or tension. Some cultures distinguish between socially approved and disapproved uses of substances by labeling those approved as "medicine" and those disapproved as "drugs." Although the word medicine derives from a Latin wordmeaning "of a physician," throughout much of recorded history and even today, "folk" medicine and "home remedies" are widely practiced. Early medicines were taken exclusively from nature, and PLANTS are still an important source of medicinal products (e.g., foxglove for heart problems, breadmoldfor penicillin).

Organic HALLUCINOGENIC substances (plants with perception-altering properties, such as peyote and mescaline, and fungi, such as psilocybin mushrooms) have been used in...