This booklet on marihuana and health begins with general observations made at a press briefing by the Director of the National Institute on Drug Abuse, followed by questions and answers. The last section contains a summary and overview of the Fifth Annual Report to the U.S. Congress from the Secretary of Health, Education, and Welfare. The information in this section includes a discussion of the extent and nature of marihuana use. Next are discussions of the chemistry and characteristics of cannabis, animal research, human effects and health implications, other chronic human effects, and therapeutic aspects of marihuana. (RC)