GENERIC NAME: ONDANSETRON - INJECTION (on-DANS-eh-tron) BRAND NAME(S): Zofran. USES: This medication is used alone or with other medications to prevent nausea and vomiting caused by cancer chemotherapy. It is also used to prevent and treat nausea and vomiting after surgery. It works by blocking one of the body's natural substances (serotonin) that causes vomiting.