This report is designed to provide useful information about marihuana to citizens for their education and enlightenment, and to Federal, state and local officials charged with making and recommending public policy concerning the use of marihuana. An attempt is made to describe the present state of knowledge, summarize progress made in the past year, and translate the disparate and technical data on the question: What are the health implications of marihuana use for the American people? Health consequences are defined as not only the effects of the drug on the individual's physical and psychological health, but also the effects of marihuana use on the society. Topics cover: (1) extent, patterns and social context of use in the United States, (2) use in other countries, (3) material and analytical methodology, (4) preclinical research in animals, (5) tolerance, (6) effects in man, and (7) therapeutic uses of cannabis. Future research directions which conclude the report recommend research in the areas of interaction between marihuana use and other drugs; adverse consequences of use; long-term use; social reinforcements of use; extensive studies on large populations of chronic users; cultural and economic studies; need for and effective means of treatment for heavy users; and therapeutic implications. A related document is ED 060 477. (BL)