Bad stomach may be functional dyspepsia, chronic gastritis, gastric ulcer, duodenal ulcer, etc. Symptoms vary from cause to cause, mainly manifested as bloating, stomach pain, nausea, vomiting, acid reflux and other symptoms. 1. Functional dyspepsia: mainly manifested as bloating, belching, bad breath, nausea, vomiting, loss of appetite and other symptoms. 2. Chronic gastritis: symptoms such as early satiety, bloating, nausea, acid reflux and heartburn. 3. Gastric ulcer: symptoms such as postprandial stomach pain, acid reflux, heartburn, nausea, loss of appetite. 4. Duodenal ulcer: manifested as abdominal pain, night pain, pain in the upper abdomen, relieved after eating, accompanied by heartburn, acid reflux, nausea, vomiting and other symptoms. If the above symptoms occur, it is recommended to consult a doctor in time and follow the doctor’s instructions to avoid delaying the condition.