Medicine and plants

In Uganda's Kibale National Park, scientists have observed chimpanzees (Pan troglodytes) searching for and then chewing the bark or leaves of plants that have very little nutritive value, but that local people use to relieve symptoms of malaria and diarrhea. The chimps also chew these plants when they are sick and they, too, use them in order to rid themselves of intestinal worms as well as to treat malaria and diarrhea. White-faced capuchin monkeys (Cebus capucinus) in Costa Rica rub plant material on their bodies, using plants that are known to have insect-repellent and other medicinal properties.

There are many instances of nonhumans—and not only primates—self-medicating with plant substances, and it seems obvious that humans must have been doing so since long before history came to be written down. It is most likely that in prehistory most human communities included a healer who relied on herbal preparations. As in many modern communities, the necessary skills would have been passed from generation to generation, but healers would also have studied the behavior of nonhuman animals in order to learn which plants to use, and almost certainly that is how the tradition began.

Depictions of medicinal herbs in the cave paintings at Lascaux, France, that are between 13,000 and 25,000 years old are the earliest record of herbal medical treatments. There is also physical evidence from antiquity. In 1991 melting of the Similaun Glacier in the Otzal Alps, Austria, exposed the mummified body of a man, subsequently nicknamed Otzi. Otzi died 5,300 years ago, aged about 45. He was carrying with him two pieces of dried birch fungus (Piptoporus betulinus) about 1.5 inches (4 cm) in diameter, each of them pierced, and both of them threaded on a single leather thong, perhaps so they could be attached to his belt. Birch fungus, also called razor strop and birch bracket, is a bracket fungus common on birch trees (Betula species). Dried, it can be used as tinder, and its cut surface was formerly used to finish sharpening very keen blades such as razors. When scientists first came across Otzi's dried birch fungus they assumed he carried it as tinder, but later they changed their minds. Birch fungus possesses antibiotic and antihelminthic—expelling parasitic worms—properties, and he might have been taking it to combat intestinal parasites.

The earliest written records include lists and descriptions of the uses of medicinal herbs. The Sumerians, living in part of what is now Iraq, were using medicines derived from plants 5,000 years ago, and in about 2000 b.c.e. King Assurbanipal of Sumeria commissioned the first catalog of medicinal plants, describing about 250. Plants were being used in this way 3,000 years ago in ancient Egypt, in India more than 2,500 years ago, and nearly 3,000 years ago in China. Indeed, until the rise of the modern pharmaceutical industry and the associated demand that therapies be administered only by licensed practitioners, herbal remedies were the mainstay of medical treatment, as they are still in many parts of the world.