The common causes of nausea and vomiting after drinking pure milk are pure milk stimulation, lactose intolerance and gastric ulcers. 1. Pure milk stimulation: Pure milk sweet taste is light, milky taste is heavy, so some people can not accept the taste of pure milk. If you can barely finish drinking pure milk, the residual milky flavor in your mouth may cause nausea and vomiting. 2. Lactose intolerance: Lactose intolerance is caused by the lack of sufficient lactase in the body. If the lactose contained in milk cannot be broken down by the enzyme lactase, when the lactose enters the digestive tract and is broken down by intestinal flora, a lot of gas will be produced, which may irritate the digestive tract and lead to nausea and vomiting. 3. Gastric ulcers: drinking milk will cause an increase in gastric acid secretion, gastric acid will stimulate the ulcerated surface of the gastric mucosa, amplifying the effect of stimulation, may lead to gastrointestinal spasms, thus causing nausea and vomiting. If you are nauseous and want to vomit after drinking pure milk, you should go to the hospital to find out the cause of the disease, do not delay.