Marijuana smoking: effect on expired air carbon monoxide levels.

A group of regular marijuana smokers was given expired air carbon monoxide (CO) tests before and after smoking low-dose, high-dose, and placebo marijuana cigarettes. Expired air CO doubled following smoking. There were no significant differences in CO levels in the different dose categories. Studies of the effects of marijuana on the body should attempt to separate effects of the drug from the effects that are secondary to the method of intake.

RCT Entities:   Population Interventions Outcomes