Five and a half month old babies are young, poor digestive function, intestinal micro-ecosystem is not established soundly, once the diarrhea is very easy to dehydration and secondary infections, so it should be actively treated. You should buy hypotonic oral rehydration salts for your baby to prevent and correct dehydration, and then at the same time give your baby probiotics to regulate the imbalance of the intestinal micro-ecosystem. In addition, we should also pay attention to give the baby fasting montelukast, or the elimination of cardotoxin, etc. used to stop diarrhea. Of course, it is also important to pay attention to good dietary management, because the digestive function is reduced in diarrhea, you should feed small amounts of multiple meals. If breastfeeding, the mother should avoid oily, irritating and allergy-prone foods, such as eggs. In case of cow’s milk feeding, it is considered that intestinal viral infections may be secondary to lactose intolerance, and lactase should be added to the baby to help digest lactose. More attention should be paid to good perianal and perineal hygiene to prevent cross-infection and the occurrence of diaper rash.