Lactose intolerance, also known as lactase deficiency, is a common clinical disease of the digestive system. After drinking or consuming milk and dairy products, patients cannot completely digest lactose in food because of the low lactase content or low activity in the body, and then a series of uncomfortable symptoms may occur. 1. abdominal pain: lactose that cannot be digested and absorbed by the body reaches the colon and stimulates the gastrointestinal wall, which may cause stomach pain or abdominal pain around the navel. 2. abdominal pain; 2, diarrhea: lactose in the intestine can not be completely digested and absorbed, often appear symptoms of diarrhea, characterized by thin, mucus or foam, occurring more urgently, if infants and young children will also appear egg-like diarrhea; 3, bloating: after taking dairy products, lactose in dairy products into the body, can not be completely digested and absorbed by the body, decomposition and fermentation under the action of intestinal bacteria, generating a lot of gas, thus 4, hyperactive intestinal sounds: after using dairy products, lactose that cannot be completely digested and absorbed by the body decomposes under the action of intestinal bacteria, and the gas produced pushes the intestinal peristalsis of lactose intolerant patients to increase, and the gastrointestinal movement leads to hyperactive intestinal sounds, manifested as stomach grumbling; 5, other: some people with more serious lactose intolerance may have allergies, eczema, headache, dizziness, nausea and vomiting, and even hypothermia. Even symptoms of hypothermia. If you have significant discomfort after consuming milk or dairy products, you can stop eating them immediately and try not to consume them or consume them less in the future. If the symptoms are severe, you can seek medical attention as soon as possible to avoid danger.