The term "club drugs" has been used in referring to drugs used primarily by young adults while at dance clubs and "raves;" however, these drugs are also being used in other social settings such as bars, college campuses, and high school parties and gatherings. Drugs that have been labeled "club drugs" include MDMA (ecstasy), GHB, ketamine, and rohypnol. Drugs not labeled as "club drugs" are also used in these social settings, such as methamphetamine, LSD, and marijuana. A new trend among youth is to have "pharming parties," held for the purpose of exchanging prescription medications that produce "highs." These include medications that are types of stimulants, narcotics, and depressants. This brochure provides detailed information on the characteristics and effects of ecstasy, GHB, ketamine, and rohypnol. The brochure also lists chemicals that have been sold as ecstasy substitutes or have been found in tablets or capsules under the claim of being ecstasy. This can increase the risks of consuming tablets or capsules believed to be ecstasy. Emergency-department data are provided on the number of cases that involved the following drugs for each year from 1994 through 2002: GHB/GBL, ketamine, LSD, MDMA, and methamphetamine.