Emend (Aprepitant) is used with other medications to help prevent nausea and vomiting caused by cancer drug treatment (chemotherapy). This medication is also used to prevent nausea and vomiting after surgery. Aprepitant works by blocking one of the body's natural substances (substance P/neurokinin 1) that causes vomiting.
This medication will not treat nausea or vomiting that has already started. Ask your doctor what you should do if you already have nausea or vomiting.