Vomiting accompanied by nausea is a serious acute toxicity which occurs after chemotherapy with virtually every class of cancer chemotherapeutic agents. The inability to adequately alleviate this toxicity may lead to serious complications such as general malaise, weight loss, and electrolyte imbalance. We have reviewed 34 studies in which more than 2200 cancer patients were administered 25 different antiemetics for treatment of chemotherapy-induced vomiting. All patients received a variety of cancer chemotherapeutic agents given either as single agents or in combination. The antiemetic agents included phenothiazines, antihistamines, anticholinergics, benzoquinolizines, barbiturates, butyrophenones, procainamides, cannabinoids, steroids, and benzodiazepines. It is apparent from these studies that the use of conventional antiemetic agents for treating cancer chemotherapy-induced vomiting is of marginal value, and the use of investigational antiemetic agents show conflicting results as to efficacy. More quantitative measures for evaluating emesis need to be defined, and the implications that a particular antiemetic therapy may be efficacious for some but not all classes of cancer chemotherapeutic agents need to be evaluated.