One of the major aspects of biodiversity is its value, which is designated by its resources. Much interest in drug plants was evinced during the early period of civilization. The use of plants for curing various human ailments has prominently figured in ancient manuscripts such as ‘The Rigvedas’, ‘The Bible’, ‘The Iliad’, ‘The Odyssey’ and ‘The Sushrtsanhita’.The History of Herodotus’. The ancient Chinese were using drug plants more than six centuries ago. They were the pioneers in using plants as valuable source of medicine. There are numerous Sanskrit writings which explain the usage, collection and isolation of drugs from plants. The Assyrians, Babylonians and ancient Hebrews were all familiar with the use of plants as drugs. Some of Egyptian papyri, written as early as 1600 B.C., mention plants such as Cannabis, Opium and Cassia being used by the physicians. The Greeks were familiar with the works of Aristotle, Hippocrates, Pythagoras, and Theophrastus. However, even during highly developed civilization, the ‘supernatural power’ was still considered supreme in healing the sufferer of various diseases. During this period, only a few men were considered able to distinguish between valuable and harmful plants. The Romans were less interested in healing plants. However, in 77 B.C. Dioscorides wrote his great treatise, ‘De Materia Medica’, which dealt with nature and properties of all the medicinal substances known till that time. This treatise completely changed the