Melatonin is not a drug, but a kind of health care product, the side effects are not clear, but a one-time consumption of ten tablets may lead to gastrointestinal discomfort or other uncomfortable symptoms due to overdose. 1. Gastrointestinal discomfort: overdose of melatonin may cause gastrointestinal discomfort, such as abdominal pain, diarrhea, etc., part of the gastrointestinal digestive function of the patient was not good, the symptoms may be more pronounced, if the symptoms of discomfort, you should consult a doctor in a timely manner. 2. Other discomforts: some patients overdose may also have dizziness, headache and other symptoms, in addition to liver and kidney insufficiency patients, metabolic capacity is limited, overdose of melatonin may aggravate the burden on the liver and kidneys, this kind of patients, if the symptoms do not disappear for a long time, it is recommended that should be discontinued immediately. In addition, during the period of taking melatonin, we should pay attention to the prohibition of alcohol, and strictly in accordance with the instructions of the doctor to take, not to take or change the dosage, to avoid overdose caused by discomfort.