The low pH in the small intestine prevents the dissolution of certain primary bile acids and reduces the formation of lipid microclusters. What enters the small intestine is glucose, peptide chains, pepsin, gastric amylase, and a little bit of unbroken starch. At this point, glucose can be absorbed directly by the small intestine, while the peptide chain continues to be broken down into thousands of amino acid molecules by enteropeptidase, and then it can be absorbed directly by the small intestine. The pH in the stomach is about 2.0, while the ambient acidity of the small intestine is much smaller than that, about 6.8, so pepsin and gastric amylase are inactivated and broken down by the small intestine. Pathogenesis of low ph in the small intestine: Low pH in the small intestine prevents the solubilization of certain primary bile acids and reduces the formation of lipid microclusters, which are necessary for the absorption of fatty acids and monoglycerides. Patients with gastrinoma may have malabsorption of vitamin B12 independent of endocannabinoids. Although the gastric secretion of endocannabinoids is normal, low pH in the small intestine interferes with the function of endocannabinoids to facilitate the absorption of vitamin B12 in the distal jejunum, which is restored when the luminal pH is adjusted to 7. Low pH in the small intestine is commonly seen in gastrinomas. Gastric ulcer perforation: Acute perforation is one of the most common and serious complications of gastric ulcer, and hospitalization for ulcer perforation accounts for about 20% of hospitalizations for ulcer disease. It has been reported that the morbidity and mortality rate of gastric ulcer perforation is 27%, the older the age, the higher the morbidity and mortality rate can rise rapidly over 80 years old, the morbidity and mortality rate is related to the length of time of surgical treatment after perforation, it is reported that the morbidity and mortality rate increases rapidly after surgery only after 6h of perforation. Stomach cancer is one of the most common malignant tumors in China, and its incidence rate is the first among digestive tract tumors in China, and about 170,000 people die from stomach cancer every year, which is a serious threat to people’s health. Gastric cancer can occur at any age, but it is more common between 40 and 60 years old, more men than women, about 3:1.