Two grams of<unk> <unk> , commonly known simply as<unk> , and also known as rock, is a free base form of<unk>  that can be smoked.<unk>  offers a short, intense high to smokers. The Manual of Adolescent Substance Abuse Treatment calls it the most addictive form of<unk> . A<unk>  addict is known as a<unk> head".<unk>  first saw widespread use as a recreational drug in primarily impoverished neighborhoods in New York City, Philadelphia, Baltimore, Washington, D.C., Los Angeles, San Francisco, and Miami in late 1984 and 1985; this rapid increase in use and availability was named the<unk>  epidemic", which began to wane in the 1990s. The use of another highly addictive stimulant drug, crystal meth, ballooned between 1994 and 2004.
Crack cocaine
Khat
Monkeypox
Herbal smokeless tobacco
Nicotine polacrilex
Dissolvable tobacco
Herbal cigarette
Areca nut