Hi Welcome to HCM. I appreciate your concern for the safety of Melatonin during childhood. The most common side effects of Melatonin include: daytime sleepiness, headache, dizziness, abdominal pain and irritability. It is mainly used for jet lag (long journey passengers) for adjusting sleep-wake cycles in people whose daily work schedule changes (shift-work disorder), etc. In children it is also used for lack of sleep (insomnia) associated with attention deficit-hyperactivity disorder (ADHD). The prolonged use of Melatonin (basically a hormone) may interfere with other hormones like male sex hormones, insulin, etc. and thus may have an adverse impact on their sexual development during adolescence. In view of the possible adverse effects on the male sex hormones, it is to be avoided for prolonged use. You are advised to consult the treating pediatrician for possible alternate drug. Hope this answers your query. A feed back is appreciated.