Stomach discomfort after drinking a lot of water can be caused by drinking too much water too quickly, indigestion and gastric ulcers. 1. Drinking too much water too quickly: if the patient drinks too much water too quickly or the water temperature is too cold, it may cause gastrointestinal tract irritation, thus causing the patient to feel sick in the stomach. 2. Dyspepsia: If patients with dyspepsia drink a lot of water, it may increase the burden on the gastrointestinal tract and reduce the digestive function of the patient’s stomach, resulting in dilatation of the patient’s stomach, which may make the patient feel sick in the stomach. 3. Gastric ulcer: patients with gastric ulcer, due to the protective barrier of the mucous membrane of the stomach wall has been damaged, after a sudden large amount of water, too much water in the stomach will lead to a sudden increase in the body of the stomach, which will also induce the phenomenon of stomach discomfort. When patients have stomach discomfort after drinking a lot of water, they should go to the hospital in a timely manner, to clarify the cause of the disease and then actively treat it, so as not to delay the condition.