Onseron Syrup 50 ml – Nausea & Vomiting ReliefOnseron Syrup 50 ml Ondansetron for Effective Nausea and Vomiting Relief Onseron Syrup 50 ml contains Ondansetron, a powerful antiemetic medicine used to prevent and treat nausea and vomiting associated with cytotoxic chemotherapy, radiotherapy, and surgery. Ondansetron works by blocking serotonin (5 HT3) receptors in the central and peripheral nervous systems, which are responsible for triggering the vomiting reflex after serotonin release from