This medication is used alone or with other medications to prevent nausea and vomiting caused by cancer drug treatment (chemotherapy) and radiation therapy. It is also used to prevent and treat nausea and vomiting after surgery.

Side Effects:
Headache, lightheadedness, dizziness, drowsiness, tiredness, or constipation may occur.

Precautions:
You should not use ondansetron if: you are also using apomorphine (Apokyn), you are allergic to ondansetron