Paloset 0.5 mg is a medication primarily used to prevent and treat nausea and vomiting caused by chemotherapy, radiotherapy, or surgery. It contains palonosetron, which is a selective 5-HT₃ receptor antagonist. By blocking serotonin receptors in the gastrointestinal tract and central nervous system, palonosetron effectively prevents the vomiting reflex, making it a useful treatment for patients undergoing chemotherapy, radiotherapy, or postoperative recovery.