There is no fastest treatment for diarrhea in children. It may be caused by irritable bowel syndrome, acute gastroenteritis, lactose intolerance and other diseases, which need to be treated with medication and surgery according to the cause. 1. Irritable bowel syndrome: typical symptoms include abdominal pain, diarrhea, constipation and so on. Children need to follow the doctor’s advice to try to regulate the diet to treat, if the effect is not good, you can use probiotics (such as bacillus subtilis bacillus granules) and other medications. 2. Acute gastroenteritis: the common symptoms of this disease include abdominal pain, diarrhea, vomiting and so on. If it is caused by viral infection, it can be cured by itself without special treatment; if there is bacterial infection, it is necessary to follow the doctor’s instructions to apply cephalosporin antibiotics such as cefuroxime and cefazolin. 3. Lactose intolerance: the main symptoms include abdominal distension, diarrhea, nausea, hyperactive bowel sounds and so on. Children need to follow the doctor’s instructions to apply probiotic drugs such as Clostridium casei, yeast, etc., and also actively cooperate with the doctor to supplement lactase. All of the above medications need to be used under the guidance of a doctor, avoid self-medication. There are many causes of diarrhea in children, you need to go to the hospital to do the relevant examination, to clarify the specific cause of the disease, and cooperate with the doctor to actively treat the original disease.