The causes of diarrhea mainly include infectious diarrhea and non-infectious diarrhea. In the case of infectious diarrhea, symptoms such as fever may be combined, and the most common pathogens are rotavirus, Escherichia coli, Salmonella, dysentery bacillus, Campylobacter, etc. In the case of non-infectious diarrhea, the main causes include improper dietary care, allergic food stimulation, lactose intolerance, etc. The main treatment for diarrhea is to actively hydrate and maintain the water-electrolyte balance, and then to treat the cause. If the child has no symptoms such as vomiting, it is recommended to drink more water or take oral rehydration salts. If the gastrointestinal symptoms are severe or dehydration is serious, intravenous rehydration support is recommended. For etiological treatment, if the diarrhea is caused by bacterial infection, antibacterial drugs, such as third-generation cephalosporins, need to be used; if it is caused by improper diet or lactose intolerance, good dietary care is needed. Therefore, babies with diarrhea must be rehydrated in time, and then targeted treatment plans should be made according to the cause. During treatment, the mental state of the child needs to be observed, and once severe dehydration, poor spirit, irritability and crying without tears occur, it is recommended to seek timely medical attention at a specialist hospital.