A drug is any substance that can be used to treat an illness, relieve a symptom or modify a chemical process in the body for a specific purpose. The term is necessarily a vague one, being defined by intent: for example, foods consumed for normal metabolism are not generally considered "drugs", but the same foods consumed for a more specific purpose (such as the use of alcohol as a depressant or caffeine as a stimulant) may be.
Many enhancing drugs are also used for recreational purposes.
Regulations Usage of most of drugs is regulated to some extent. While details vary with location, these are somewhat usual regulations:
Regulated to some extent (age or labeling requirements, for example) but available over the counter:
Prescription drugs[?], prohibited for non-medical use:
Varies from tolerated to prohibited even for medical use:
Varies from prohibited for non-medical use to prohibited for any use
Prohibited for any use, no medical uses currently allowed most of the time
Three international UN treaties regulate drug laws:
The UN Office for Drug Control and Crime Prevention (http://www.undcp.org/) is charged with overseeing these treaties and maintains a list of signatory nations at http://www.undcp.org/treaty_adherence.