Marijuana or Cannabis is a weed which grows in many different parts of the world. The plant may be altered into different forms to allow various forms of ingestion. Although marijuana's psychoactive properties have been known for almost 5,000 years, the plant first attracted public attention in the United States during the first half of this century, and then became widely known during the 1960s. Marijuana is commonly smoked, producing a euphoria which lasts approximately two hours. While the drug induces side effects such as enhanced taste, touch, hearing, and vision, it also inhibits memory; accelerates the heart beat; impairs muscular coordination, time, and space judgment; impairs driving abilities; leads to lung disease; promotes birth defects; and may impede the immune system's function. Controversy still surrounds the social and medical consequences of marijuana use and debate continues on whether the drug leads to chromosome damage. Legal penalties for marijuana use vary widely in the states and drug testing has become commonplace. Analytical testing techniques may detect minute levels of marijuana's psychoactive ingredients in bodily fluids but these tests do not necessarily reveal whether the person is intoxicated or how recently marijuana may have been used. (RJM)