A comprehensive review of the established physiologic and metabolic effects of marijuana in relation to cardiovascular physiology and stress-response mechanisms has been presented. This information is related to the preoperative and postoperative treatment of the dental patient who smokes marijuana habitually. Marijuana is not a benign drug. Its vasoactive, cardiotropic, steroidogenic, and enhanced sympathoadrenal stress-response effects justify caution when administering atropine or epinephrine-containing products to the habitual user of marijuana. More clinical as well as laboratory research is needed to elucidate the speculation regarding a drug so frequently misused.