There are two main conditions that cause stomach acid in the morning, one is a physiological cause and the other is caused by pathological factors. Physiological causes are caused by the following factors: 1, due to improper diet, eating indigestible food such as chocolate, etc. The sugar in these foods is not completely absorbed in the stomach and intestines, it will slowly ferment and lead to excessive stomach acid. In addition, eating high starchy food will also appear stomach acid. 2, mental stress, patients with high mental stress will lead to endocrine disorders and abnormal gastric acid secretion. Pathological factors are mainly gastrointestinal diseases, such as chronic gastritis, duodenal ulcer, etc.. There are also genetic factors, as genetic factors are different, so each person’s body constitution is different, and the level of gastric acid secretion will be different for different constitutions.