Hi, Ondem MD 4 mg contains ondansetron which is an antiemetic medicine commonly used to control nausea and vomiting due to certain medical conditions like stomach upset. It is also used to prevent nausea and vomiting caused due to any surgery, cancer drug therapy or radiotherapy. Your doctor will suggest the appropriate dose depending on what you are taking it for. Take it regularly at the same time each day to get the most benefit. Be careful not to take too much. Most common side effects of Ondem MD 4 mg are fatigue, dry mouth, dizziness, drowsiness, feeling tired, diarrhoea or constipation, stomach pain, headache etc. These symptoms should disappear when you stop taking the medicine. However, if these side effects bother you or don t go away, consult your doctor and he may be able to suggest ways of preventing or reducing them. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Zubayer Alam, General And Family Physician,