Low pepsinogen I is usually indicative of damage to the gastric fundus and body mucosa or conditions such as atrophy, and requires aggressive treatment to improve the prognosis. It is usually necessary to analyze the ratio between I and II together with pepsinogen II. Pepsinogen I and ratio are reduced in those with atrophy of the gastric body, total gastric atrophy and gastric cancer. It is usually caused by diet, drugs, poor rest and other factors. Gastritis, Helicobacter pylori infection and gastric cancer can also cause low pepsinogen I. Treatment requires active treatment of the primary disease and corresponding treatment: 1, gastritis: attention should be paid to dietary hygiene, regular diet, avoid eating too hard, too acidic, too hot, too spicy food, abstain from alcohol, avoid drinking strong tea, coffee, etc. Drugs that inhibit gastric acid secretion and protect the gastric mucosa, such as cimetidine, aluminum preparations, etc., can be used under the guidance of a doctor; 2, H. pylori infection: H. pylori quadruple therapy can be used therapy, that is, a proton pump inhibitor + two antibacterial drugs + a bismuth agent; 3, gastric ulcer: can be treated with drugs that inhibit acid and protect the gastric mucosa, such as famotidine, omeprazole, etc. If necessary, the treatment of surgical removal of the ulcer surface can be taken; 4, gastric cancer: caused by low pepsinogen I, it is recommended to actively carry out surgery, as well as the necessary chemotherapy, targeted therapy to improve the cure rate.