If a 4-year-old child has diarrhea, but not accompanied by abdominal pain, fever and other symptoms, just diarrhea, the number and amount of diarrhea are not large, you can take some oral montelukast to protect the intestinal mucosa, and then feed more sugar and salt water, or drink more porridge can be, let him slowly recover, may be a viral diarrhea. If your baby has abdominal pain and diarrhea because he or she has eaten a lot of food that is not too easy to digest, it may be that your baby has accumulated food, so you can give him or her as few meals as possible and improve his or her diet by drinking the oral liquid or Si Mo Tang, which may have some effect. If your baby has abdominal pain and fever in addition to diarrhea, and the diarrhea symptoms are also serious, it is likely that your baby has some kind of bacterial infection in the intestines. At this time, it is best to take him to the hospital for some tests and then proceed to the next step of treatment.