Marijuana has the distinction of being the most widely used illicit drug in the United States. This video traces the history of marijuana and goes on to explain some of the many uses of the hemp plant; the effects of THC—the primary psychoactive chemical in marijuana, sinsemilla, hashish, and hash oil—on the body; the short- and long-term health implications of marijuana abuse; and teenage attitudes toward marijuana. In addition, the video investigates the concept of psychological dependency and considers whether marijuana is a gateway drug. A viewable/printable instructor’s guides is available online. A Cambridge Educational Production. (19 minutes)