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Illegal Drugs

Illegal drugs are those that are not prescribed by a doctor or bought at a drugstore. They are sometimes also called "street drugs."

Some examples of illegal drugs include heroin (a narcotic); cocaine (a stimulant); LSD, mescaline, PCP, methamphetamine, and psilocybin (hallucinogens); marijuana and hashish (cannabis); and gamma-hydroxybutyrate (GHB). Although GHB is legal in Europe for anesthetic uses and in the United States for government-approved clinical trials for treating narcolepsy, it has been otherwise illegal in the United States since 1990.

The effects of illegal drugs can be unpredictable because:

  • Most drugs are very addictive.
  • People respond differently to the same drugs.
  • The strength or potency of the drug may be uncertain.
  • They may contain unknown or unexpected substances. There is no quality control for street drugs like that required for prescription drugs.
  • They may interact with other drugs or alcohol in unpredictable ways.
By Healthwise Staff
Primary Medical Reviewer William H. Blahd, Jr., MD, FACEP - Emergency Medicine
Specialist Medical Reviewer Peter Monti, PhD - Alcohol and Addiction
Last Revised October 13, 2011

WebMD Medical Reference from Healthwise

Last Updated: October 13, 2011
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.