Definition of Drug

A drug is defined as any substance that, when taken internally (e.g. swallowed or injected into the body) modifies one or more bodily functions - such as physical functions, cognitive functions, immune system functions, etc.

Technically, the classification of drug includes not only medication and drugs of abuse but also such substances as alcohol, caffeine and nicotine.

Further Reading:

Article : "GINKGO"

by Catherine E. Myers. Copyright © 2006 Memory Loss and the Brain