If your child has diarrhea when he has a fever, if he is in good spirits and has a good diet, he can drink more water, which will help to lower his body temperature and prevent dehydration caused by high fever and diarrhea. You can take pediatric cold and flu granules orally, which can treat and relieve the symptoms of fever caused by common cold and influenza. It can be combined with Chinese medicine, such as Blue Scutellaria Oral Liquid, Pudilan Anti-inflammatory Oral Liquid and other heat-clearing and detoxifying drugs. It can be combined with antibiotic drugs such as cefixime and azithromycin syrup to control the infection. If the body temperature exceeds 38.5℃, you can take oral ibuprofen suspension, which has the effect of rapidly reducing fever. You can take oral domperidone suspension and stomachic oral solution, which can promote the peristalsis of the gastrointestinal tract and improve the diarrhea. If the diarrhea is more serious, you can take oral montelukast, which has the effect of fixing the intestines and collecting astringency.