“[T]he effects of smoked marijuana on emesis were mild. Marijuana had a modest effect on nausea, queasiness and emesis in this model of nausea induced by syrup of ipecac. The comparison drug, ondansetron, totally eliminated both the subjective feelings of nausea and the emesis. These findings confirm clinical reports that smoked marijuana can reduce nausea, but relative to the potent effects of ondansetron and because of its psychoactivity, its usefulness in the clinical setting is likely to be limited.”