Common dairy products, such as breast milk, milk, formula, goat milk, etc. contain a nutrient called lactose. Lactose cannot be absorbed directly by the body, but needs to be broken down under the digestive action of lactase ah before it can be absorbed by the digestive system. Lactose intolerance is a series of symptoms and reactions caused by the body’s normal ability to secrete lactase being weakened or missing, and the lactose in dairy products not being absorbed. Common symptoms of lactose intolerance in infants and young children include vomiting, bloating, diarrhea, abdominal pain, intestinal thunder and exhaust, milk flaps in stool, etc. Due to abdominal discomfort, it is easy to produce crying. If your baby has the above symptoms, it is recommended to go to the hospital to do a urine galactose or stool test. If some local hospitals are not equipped to do the test, you can also judge by the self-identification method summarized by experts: three looks and one smell. Look at the baby’s stool: there is no milk flap, there is no watery stool separation of egg white soup-like, there is a lot of foam. Listen to the baby’s stomach: is it often gurgling with intestinal sounds, is it more farts. Smell the baby’s mouth: there is no sour smell. If 1-2 items meet, you can basically conclude that for mild lactose intolerance; three or more, belong to moderate to severe lactose intolerance.