Children’s diarrhea, whether it is a viral infection or bacterial infection, should be comprehensively analyzed from its clinical manifestations, test results, pathogens, etc. Viral infections mostly cause watery stools, fecal leukocytes are often negative; bacterial infections are more pasty, and most of the fecal leukocytes are positive. Viral infections are characterized by fever, vomiting, egg-like watery stools, and a high number of stools, up to 10 times a day. Bacterial infections are characterized by fever, pasty or mucus-like stools. When testing the stool routine, for viral infections, fecal leukocytes and pus cells may be positive in the case of rotavirus or norovirus; for the rest of the viral infections, most of these two cells are normal in the feces; and for bacterial infections, the feces are usually positive for these two cells. Children’s diarrhea is recommended to consult the doctor as soon as possible, after a clear diagnosis of timely and targeted treatment, to avoid delaying the best time for treatment.