The common causes of diarrhea in a 3-year-old boy for 3 consecutive days include abdominal cold, gastrointestinal tract dysfunction, gastroenteritis, etc. Relief methods include physical therapy, medication such as montelukast, amoxicillin, and others. Different causes, the choice of relief methods are also different. 1. Cold abdomen: The symptoms of diarrhea appear due to the irritation of the mucous membrane of the gastrointestinal tract caused by inadequate warming measures. Physical therapy, such as hot compresses and massages, can be chosen to promote local blood circulation in the abdomen and help better digestion and absorption of food, thus relieving the symptoms. 2. Gastrointestinal tract dysfunction: Due to the dysfunction of the gastrointestinal tract of the child, the gastrointestinal tract moves faster, which triggers diarrhea symptoms in the child. You can choose medication, such as montelukast, bifidobacteria, etc., to stop diarrhea and regulate the intestinal flora, so as to improve the symptoms. 3. Gastroenteritis: Inflammation and infection of the gastrointestinal tract due to unclean food and drink can cause diarrhea in children. You can choose medication, in addition to symptomatic treatment, but also choose to use antibiotics, control bacterial infection, such as amoxicillin, penicillin, cefuroxime sodium and so on. If the child has diarrhea for three consecutive days, it is recommended that the parents take the child to the hospital in time to improve the relevant examination, to clarify the cause of the disease, and comply with the doctor’s instructions for treatment.