Pharmacognosy is the study of medicines derived from natural sources. The American Society of Pharmacognosy defines pharmacognosy as "the study of the physical, chemical, biochemical and biological properties of drugs, drug substances or potential drugs or drug substances of natural origin as well as the search for new drugs from natural sources. "It is also defined as the study of crude drugs. The word "pharmacognosy" is derived from the Greek words pharmakon (drug), and gnosis (knowledge).