Mescaline derived from Lophophora williamsii buttons or semi-synthetic refinements commonly causes initial nausea. This first phase of intoxication may even provoke active vomiting. This is probably related to it's chemical similarity to both dopamine and norepinephrine. Drugs that potentiate dopamine are potent emetics. In other words, an excess of them can make you hurl. On the other hand, this gastrointestinal upset may be related to it's possible use as an anti-biotic.