Diarrhea after fever reduction is normal because it is mainly seen after viral infections, such as viral upper respiratory tract infections, herpes pharyngitis, hand, foot and mouth disease, and herpes simplex infections of the skin. As these viral diseases are recovering from treatment, a large number of viruses can enter the intestine and replicate in the intestine, resulting in congestion, edema and exudation of inflammatory cells in the intestinal mucosa, and even damage to the intestinal mucosa, all these factors can stimulate the intestinal peristalsis to speed up, and the water in the intestine cannot be fully absorbed by the intestine, and diarrhea occurs. This condition is mainly seen in children, mainly because children’s intestinal immune function is weaker. The main treatment is to give rehydration, protect the intestinal mucosa, adjust the intestinal flora and other treatment, generally do not need to give antiviral drug treatment.