Sexual assault among college students, especially at social functions and parties, often involves drug or alcohol consumption by both the victim (forced or voluntary) and the offender. The effect is to impair the judgment of both the victim and the offender. Recently, there has been an increase in the number of substance-related sexual assaults throughout the United States. Many experts suggest this may pose a new dilemma in Canada within the near future. Offenders use drugs and alcohol to sedate their victims. Two substances that are frequently used include Gamma Hydroxybutyrate (also referred to as GHB) and Rohypnol ("Roofies"), the trade name for flunitrazepam. Although these two substances have received recent media attention, many sedating substances have been used to achieve the same goal, including alcohol, common cold pills, other sedatives, and other illegal narcotics. This article reviews the characteristics and effects of GHB and Roofies. An outline of prevention strategies for potential victims includes keeping their drink with them at all times; not taking drinks from strangers other than a bartender, waiter, or waitress; and not accepting open container drinks at parties. College and high school guidance counselors and administrators should be briefed on this issue by police crime prevention or juvenile division officers. Police should ensure that any person who claims to have consumed a sedative-like substance should be immediately taken to a hospital emergency room. A urine test to determine the presence of sedating substances should be performed as quickly as possible. The chances of collecting evidence are best when the sample is obtained soon after it has been ingested. Police should be knowledgeable about drug-related rape so they can exercise sensitivity to victims and use appropriate investigative techniques.