The most commonly used illegal drug in the U.S. The main active chemical is THC.

Aunt Mary, Boom, Chronic (Marijuana alone or with crack), Dope, Gangster, Ganja, Grass, Hash, Herb, Kif, Mary Jane, Pot, Reefer, Sinsemilla, Skunk, Weed.

Short-term effects of marijuana include problems with memory and learning, distorted perception (sights, sounds, time, touch), trouble with thinking and problem solving, loss of motor coordination, increased heart rate, and anxiety.These effects are even greater when other drugs are mixed with weed.  A user may also experience dry mouth and throat.

Marijuana smoke contains some of the same cancer-causing compounds as tobacco, sometimes in higher concentrations.Studies show that someone who smokes five joints per week may be taking in as many cancer-causing chemicals as someone who smokes a full pack of cigarettes every day.

Schedule I

In 2006, 25 million Americans age 12 and older had abused marijuana at least once in the year prior to being surveyed. Source: National Survey on Drug Use and Health; http://www.samhsa.gov/. The NIDA-funded 2007 Monitoring the Future Study showed that 10.3% of 8th graders, 24.6% of 10th graders, and 31.7% of 12th graders had abused marijuana at least once in the year prior to being surveyed. Source: Monitoring the Future http://www.monitoringthefuture.org/.