With the advent of new chemotherapeutic agents, and their well-known side effect of emesis, the need for a greater facility with anti-emetics has emerged. As well as the common problem of chemotherapy-induced emesis, other problems have become apparent such as delayed emesis and anticipatory emesis. The control of such emetic problems may be affected by certain patient characteristics, such as a history of chronic high alcohol intake, and age. Blockade of the different types of neuroreceptors can lead to effective emetic control. Dopamine receptor blockers such as the phenothiazines, butyrophenones and substituted benzamides have been among the most effective agents. However, newer agents, such as ondansetron, which specifically bind to serotonin receptors, may preserve the anti-emetic efficacy of the dopamine-blockers, but without the associated extrapyramidal side effects of these agents.