What is drug?
A drug is any chemical or biological substance, synthetic or non-synthetic, that when taken into the organism’s body, will in some way alter the functions of that organism. This broad definition can be taken to include such substances as food. In these cases the word “drug” is usually used to refer specifically to medicine. Many natural substances such as beers, wines blur the line between food and drugs, as when ingested they affect the functioning of both mind and body. Drugs are usually distinguished from endogenous biochemicals (substances originate from within an organism) by being introduced from outside the organism. For example, insulin is a hormone that is synthesized in the body; it is called a hormone when it is synthesized by the pancreas inside the body, but if it is introduced into the body from outside, it is called a drug.
