A drink of milk on the stomach pain may be lactose intolerance, indigestion, gastritis, gastric ulcer and other conditions lead to. 1. Lactose intolerance: due to the lack of lactase enzyme in the patient’s body, after drinking milk in the milk lactose can not be digested lactose intolerance, and then the situation of stomach pain, this time the patient will often be accompanied by diarrhea associated with eating milk obviously. 2. Indigestion: if the patient usually indigestion, gastric power is not enough, so that the casein in the milk in the stomach stays too long, will also lead to a drink of milk or eat after the stomach pain. 3. Gastritis: usually gastritis patient’s stomach mucosa in the long-term inflammation of the state, the casein in the milk is difficult to digest, thus causing stomach pain. 4. Gastric ulcer: drinking milk will stimulate the secretion of gastric acid, gastric acid stimulation of the stomach wall, for gastric ulcer patients will cause obvious abdominal pain, resulting in a drink of milk stomach pain. There may be other causes of stomach pain when drinking milk, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.