Although the potential for viral transmission is considerable in shooting galleries as a result of the multiple use of injection equipment, exchanges of sex for drugs are not particularly common. They occur, but not with great frequency. By contrast, however, sex-for-drugs exchanges are commonplace in many crack houses—places where crack cocaine is sold and smoked.

Crack is a variety of cocaine base, produced by cooking cocaine hydrochloride in boiling water and baking soda. It has been called the "fast-food" variety of cocaine, and is popular in the United States because it is cheap, it is easy to conceal, it vaporizes with practically no odor, and the gratification is swift: a short-lived (up to five minutes) but nevertheless intense, almost sexual euphoria. Smoking cocaine as opposed to snorting it results in more immediate and direct absorption of the drug, producing a quicker and more compelling high, which greatly increases the potential for dependence (Inciardi, 1987, 1992; Wallace, 1991). For many users, once crack is tried it is not long before it becomes a daily habit.

Users typically smoke for as long as they have crack or the means to purchase it—money, personal belongings, sexual services, stolen goods, or other drugs. It is rare that smokers have only a single "hit" of crack. More likely they spend $50 to $500 during a three-or four-day binge, smoking almost constantly. During these cyclical binges, crack users neglect food, sleep, and basic hygiene, severely compromising their physical health. In addition, mouth ulcerations and burned lips and tongues from the hot stems of the pipes are not uncommon, and many smokers have reported and have been observed to have untreated STDs (Inciardi, Tims, and Fletcher, 1993; McCoy and Miles, 1992; Ratner, 1993).

The use of crack first became popular in many inner-city communities in the United States during the mid-1980s, and shortly after the drug was noticed by the media, press and television reports began describing crack use as an "epidemic" and a "plague" that was devastating entire communities (Inciardi, 1987). Considerable focus was placed on how the high addiction liability of the drug instigated users to commit crimes to support their habits, how crack engendered a so-called hypersexuality among users, and how the drug was contributing to the further spread of HIV and AIDS (Gross, 1985; Hackett and Lerner, 1987; Kerr, 1986a,b, 1988; Lawlor, 1986; Lee, 1988; Minebrook, 1989; Morganthau and McKillop, 1986; Raab and Selwyn, 1988; Seligman, 1986; Time, 1988).