Poor digestion, stomach bloating and upper body acidity may be caused by gastritis, gastric ulcer, gastric cancer and other stomach diseases. 1. Gastritis: including acute gastritis and chronic gastritis, it will lead to different degrees of damage to the gastric mucosa, and the secretion of gastric acid is high, which often leads to symptoms such as loss of appetite, gastric bloating and stomach acid. 2. Gastric ulcer: mainly occurs when the mucous membrane or deeper layer of the stomach wall is ulcerated, which affects the digestive function of the stomach to a certain extent, and it is easy to suffer from indigestion, and due to the existence of ulcers on the mucous membrane of the stomach, it is easy to suffer from symptoms such as bloating, heartburn, stomach acidity, stomach pain, and so on. 3. Gastric cancer: malignant tumors occurring in the stomach, often originated from gastric mucosa cells, early symptoms are not obvious, a few patients will have indigestion, fullness, stomach acid, stomach pain and other symptoms. Poor digestion, stomach bloating and upper body acidity may also be caused by other reasons. If the symptoms continue to be unrelieved, you should go to the hospital in time and cooperate with the doctor for examination and treatment.