Blood tests for bad stomach can generally check anti-Helicobacter pylori antibodies, routine blood tests and tumor markers. 1. Anti-Helicobacter pylori antibody: bad stomach is most likely caused by H. pylori infection, so it is necessary to test the anti-H. pylori antibody in the patient’s blood to determine whether there is H. pylori infection in the patient’s stomach. 2. blood routine: people with long-term stomach problems will have a reduced ability to absorb various nutrients, so they may have various nutritional deficiencies, especially iron deficiency anemia, so they need to draw blood for routine blood tests to check whether they have anemia. 3. Tumor markers: people who always have a bad stomach should be screened for tumor markers for stomach tumors, especially patients with significant weight loss, long-term stomach pain and loss of appetite. Patients who always have a bad stomach should go to the hospital to find out the cause without delay.