Forsetron 2mg Oral Drops is used in the prevention of vomiting and nausea that usually occur after cancer chemotherapy, radiation treatment, or surgery. It contains Ondanestron, which works by blocking the action of a chemical in the body (serotonin) responsible for causing nausea and vomiting. It may cause common side effects such as constipation, headache, diarrhea, drowsiness, flushing (a feeling of warmth), weakness, and tiredness. Before taking this medication, inform your doctor if you are allergic to any of its components or if you are pregnant/breastfeeding, and about all the medications you are taking and any pre-existing medical conditions.