Low pepsinogen I should be selected according to the different causes of different treatments, the causes mainly include gastritis, gastric cancer, gastric ulcer and so on. 1. Gastritis: Gastritis is acute and chronic inflammation of gastric mucosa caused by drugs, alcohol, degenerative changes of gastric mucosa, etc. Pepsinogen I can be used to detect the morphology and function of gastric mucosa, therefore, low pepsinogen I may be caused by gastritis, which can be treated by taking Esomeprazole magnesium enteric-coated tablets, Lansoprazole enteric-coated tablets, Clarithromycin tablets and other drugs. 2. Gastric cancer: Gastric cancer is mainly caused by cancerous transformation of epithelial cells of gastric mucosa, genetic, environmental, dietary, Helicobacter pylori infection and other factors may cause gastric cancer. Pepsinogen I can measure the function of gastric secretory gland cells, so gastric cancer may cause low pepsinogen I, which can be treated by chemotherapy, radiotherapy and surgery. 3. Gastric ulcer: Gastric ulcer mainly refers to the damage of gastric mucosa caused by gastric acid and pepsin under the condition of Helicobacter pylori infection, heredity, diet, etc. The process of damage exceeds the muscle layer of mucosa and then erosion is formed, therefore, gastric ulcer can cause low pepsinogen I. It can be treated by omeprazole enteric-coated tablets, propylenolamine tablets, famotidine tablets and other drugs. It is recommended to go to the hospital for further examination, to clarify the cause of the disease and timely symptomatic treatment, the drug should be used in accordance with medical advice.