The city representatives report increasing numbers of persons who smoke cocaine. This is believed to be due to the increasing availability in certain areas of the country of a preprocessed form of cocaine known as "crack" or "rock." Particular concern was expressed regarding the reduced time from the first use of "crack" to dependency, which has impacted the demand for treatment services. Generally, indicator data for all forms of cocaine have continued to increase in the cities; however, currently it is difficult to determine the impact that "crack" has had on these statistics. Fourteen cities reported the increasing availability of a potent form of heroin known as "black tar," "gumball," or "tootsie roll." It is insoluble in water and is being smoked rather than used intravenously. The population of heroin users appears to be aging; the gradual increase in client age along with the relative stability in users' sex and race suggests a stable prevalence of heroin addicts. The use of marijuana is prevalent in all the cities, particularly among individuals under 21 years old. Statistics on AIDS among intravenous (IV) drug users indicate that IV drug use is the most prevalent risk factor for females and the greatest seropositivity rate is for people with both IV and homosexual/bisexual behaviors. Although the country presentations were not representative of all of Western Europe, some general trends are apparent. Heroin addiction is apparently either stabilized or declining, especially among youth; cocaine use is apparently increasing, but not at the rate or prevalence reported recently in the United States.