Mescaline is a naturally occurring alkaloid contained in a San Pedro cactus or Peyote that cause hallucination. Its effects can be likened to an (Lysergic acid diethylamide) LSD and psilocybin. Known as one of the most popular type of chewing peyote, mescaline comes in a cute knob-like shape. It is also processed in laboratories for certain medical purposes. Mescaline is also referred to as 3, 4, 5-trimethoxyphenethylamine with effects analogous to catecholamine dopamine.

Mescaline has already been long used by Native Americans to create hallucinations and as part of their rituals. During the 4000 B.C., the drug is also used for medical purposes. Its antiseptic properties made it useful in disinfecting wounds. Many tribes at present times continue to use mescaline. However, because of its strong hallucinating nature, it is stringently regulated by authorities. In the United States of America, Mescaline was declared to be illegal by virtue of the Comprehensive Drug Abuse Prevention and Control Act of 1970. The United Kingdom also classified mescaline as Class A drug but its dried cactus are allowed to be sold in markets. Mescaline is also illegal in Western Australia, Queensland and Northern Territory. Nevertheless, many houses in the area continue to use the San Pedro cactus as home ornament or decoration.

The effects of mescaline are strong yet unpredictable. Native people tend to abuse the drug because it alters emotions. For instance, people suffering from extreme emotional depression take the drug to change their feelings into a positive one. However, since mescaline has high tolerance, a person may require higher dosage from prolonged used. Long term usage of mescaline can cause mental disorientation or brain damage. It also causes other symptoms like confusion, depression, and anxiety making it so difficult for a person to go back to reality.

People who are addicted to mescaline are often placed on rehabilitation centers to recover.