From earliest times mankind has used plants in an attempt to cure diseases and relieve physical suffering. Primitive peoples in all ages have had some knowledge of medicinal plants, derived as the result of trial and error. These primitive attempts at medicine were based on speculation and superstition. Most savage people have believed that disease was due to the presence of evil spirits in the body and could be driven out only by the use of poisonous or disagreeable substances calculated to make the body an unpleasant place in which to remain. The knowledge regarding the source and use of the various products suitable for this purpose was usually restricted to the medicine men of the tribe. As civilization progressed the early physicians were guided in great part by these observations.
In all the early civilizations there was much interest in drug plants. In China, as early as 5000 to 4000 B.C., many drugs were in use. There are Sanskrit writings in existence which tell of the methods of gathering and preparing drugs. The Assyrians, Babylonians, and ancient Hebrews were all familiar with their use. Some of the Egyptian papyri, written as early as 1600 B.C., record the names of many of the medicinal plants used by the physicians of that day, among them myrrh, cannabis, opium, aloes, hemlock, and cassia. The Greeks were familiar with many of the presentday drugs, as evidenced by the works of Aristotle, Hippocrates, Pythagoras, and Theophrastus. Even in their highly developed civilization, however, the supernatural element was still uppermost. Only a few men were considered able, because of some special power, to distinguish between valuable and harmful plants. These rhizotomoi, or root diggers, were an important caste in ancient Greece. The Romans were less interested in healing plants. However, in 77 B.C. Dioscorides wrote his great treatise, "De Materia Medica," which dealt with the nature and properties of all the medicinal substances known at that time. For fifteen centuries this work was held in high esteem, and even today it is valued by the Moors and Turks. Pliny and Galen also wrote about drug plants.
After the Dark Ages were over, there came the period of the herbalists and encyclopedists, and the monasteries of Northern Europe produced