ABSTRACT
As mentioned in Chapter 1, our human species’ earliest experiences with “drug effects” occurred unintentionally, as a result of intentionally eating plants for nourishment. Obviously, these effects would have to be classi! ed as “side-effects,” of sorts, since obtaining nutritive value was, of course, the real goal. Nevertheless, this paradigm illustrates an important principle in pharmacology-that drugs are usually substances that are chemically foreign to the human body (i.e., xenobiotics). Therefore, because they are produced in plants (be they botanical or pharmaceutical), they usually have to gain entrance into the body in order to produce an effect; the exception being those that produce a topical (skin) effect.
