Emitino Tabs 8mg 10'sOndansetron is used to prevent nausea and vomiting caused by cancer chemotherapy, radiation therapy, and surgery. Ondansetron is in a class of medications called serotonin 5 HT3 receptor antagonists. It works by blocking the action of serotonin, a natural substance that may cause nausea and vomiting. Ondansetron comes as a tablet, a rapidly disintegrating (dissolving) tablet, film, and an oral solution (liquid) to take by mouth. Dosage The first dose