Used primarily to prevent nausea and vomiting caused by chemotherapy, especially in patients receiving highly emetogenic (vomiting-inducing) cancer treatments. It is also effective in preventing postoperative nausea and vomiting in surgical patients. As a potent 5-HT3 receptor antagonist, it works by blocking serotonin, a natural substance in the body that can trigger nausea and vomiting. Its long half-life allows for extended protection with a single dose, making it a preferred choice in both oncology and perioperative settings.