Passive inhalation of marijuana smoke: a critical review.

A number of research studies have been published which have attempted to determine the relationship of the passive inhalation of marijuana smoke to the consequent production of urinary cannabinoids. At least superficially, most of these studies appear to support the proposition that passive inhalation should be seriously considered as a possible explanation for a positive urine test for marijuana. Examination of the experimental conditions that are required to produce positive test results indicates that passive inhalation does not have a major effect outside the laboratory and should not affect drug test results in the workplace.