Preparations from cannabis include herbal cannabis (marihuana), cannabis resin, and cannabis oil. Cannabis is more closely related to the hallucinogens than to any other class of drugs. Smoking cannabis produces intoxication of a short duration starting immediately after use and lasting from half an hour to an hour. The degree of intoxication depends on the dose taken, the characteristics of the user, the social culture, and the circumstances under which it is taken. Cannabis does not produce a physical dependence or an abstinence syndrome. Indepth studies of cannabis users have only occurred in recent years, making it difficult to give conclusive findings from research; however, about 50 researchers from 14 countries have produced new evidence about marihuana's effects on reproduction, lungs, cellular metabolism, and the brain. Proponents of the legalization of cannabis use argue that it is not addictive, that it is less harmful or no more harmful than alcohol or tobacco, and that its criminalization places its users in contact with a criminal element that pushes addictive drugs. Those supporting the continued criminalization of marihuana use argue that its harmful effects warrant its legal control, that it leads to the use of addictive drugs, and that the social and health problems created by the use of alcohol and tobacco should not be repeated by legalizing marihuana. While there is no solid evidence that the use of marihuana necessarily leads to the use of harder drugs, the serious physical effects apparently produced by cannabis use do warrant the control of its use. Twelve references are listed.