Ondansetron hydrochlorideis utilized to control nausea and vomiting provoked by cancer radiation therapy, chemotherapy, and surgery. It is in a class of medicines named serotonin 5-HT3 receptor antagonists. It functions by preventing the activity of serotonin, natural elements that may provoke sickness and vomiting. The drug reaches as a tablet, a quick-dissolving tablet, film, and an oral solution (liquid) to be consumed by mouth. The first dosage of ondansetron is often taken 30 minutes before the beginning of chemotherapy, 1-2 hours before the beginning of radiation therapy, or 1 hour before surgery. Other doses are sometimes used once a day.