Antiemetics are drugs used against nausea and vomiting that is elicited by a wide array of provocative stimuli. The principal objective of this review paper was to describe the agents that are used, current research in new mechanisms and future directions. There are seven main categories of antiemetics available in the clinics and each category has different mechanisms of action, clinical indications and adverse effects. Although emesis occurs after chemotherapy, radiotherapy, postoperatively and as a side effect of many drugs such as antidepressants, yet, there are no ideal and universal antiemetics available in the clinics because the existing antiemetics target only one or a few stimuli that trigger the reflex. Currently, researchers are trying to find methods to diminish the unwanted adverse effects of existing antiemetics and to discover new antiemetics that may be targeted at different receptors. They are also trying to explore new strategies to improve the efficacy of existing antiemetics, to develop drugs that do not cross the blood brain barrier and to discover new antiemetics for the prophylaxis and treatment of nausea.