Hi, Longifene A syrup is an ayurvedic medication used for underweight children to help them gain weight by increasing their appetite. It has some side effects too. Major side effects are anorexia, itching, emesis, burning sensation in stomach etc. Other side effects are nausea, skin rashes, vomiting, diarrhoea, headache, runny nose etc. If any of the mentioned side effects is observed, especially if they don t go away, then the medication should be stopped. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Zubayer Alam, General & Family Physician