On November 12, a 77-year-old male patient of Hubei origin was admitted to the gastroenterology department. The patient had intermittent black stools for 1 year, recurrence for 2 weeks, and hemoglobin as low as 57g/L. He repeatedly visited local hospitals and was treated effectively with acid suppression and anti-infection, but his symptoms recurred after stopping the medication, and gastroscopy and abdominal CT performed at a local tertiary care hospital 5 months ago did not show any significant abnormalities. After hospitalization, the patient was checked for hemoglobin 59g/L, and perfected gastroscopy: reflux esophagitis (LA-A grade), gastric fundic striae erosion; colonoscopy: colonic capillary dilatation, neither of which could explain recurrent gastrointestinal bleeding On November 12, a 77-year-old male Hubei patient was admitted to the gastroenterology department. The patient had intermittent black stools for 1 year and recurred for 2 weeks, with hemoglobin as low as 57 g/L. He repeatedly visited local hospitals and was treated effectively with acid suppression and anti-infection, but his symptoms recurred after stopping the medication. The patient’s family found out on the Internet that our gastroenterology department has strong comprehensive strength and good reputation, and can perform special examinations such as capsule endoscopy and double-balloon small intestine microscopy, so they went to our hospital. He was found to have 59g/L hemoglobin and perfected gastroscopy: reflux esophagitis (LA-A grade), gastric fundic erosion; colonoscopy: dilated colonic capillaries, neither of which could explain the cause of recurrent gastrointestinal bleeding. Further capsule endoscopy was performed: small intestinal parasites, hookworms, and chronic inflammation of the small intestinal mucosa. The patient had been living in Hubei for a long time, farming for a long time, barefoot in the field and applying manure, and there were susceptibility factors to hookworm. The hookworm bites the mucosal villi of the small intestine and feeds on blood, mucosal epithelium, and intestinal fluid, and changes the bite site four to six times a day, and secretes anticoagulant substances, causing blood leakage from the adsorption port. Chronic blood loss led to anemia. At this point, the cause of this occult gastrointestinal bleeding was clear – hookworm disease. Supplementation of hematopoietic material and correction of anemia were given, and albendazole 200mg/day*3 days were given, and the patient was discharged on November 22. In recent years, the gastroenterology department of our hospital has been developing and growing, not only in the Beijing area, but also more and more patients from outside Beijing, solving practical problems for more patients, which has been recognized by the industry and praised by patients. The reason, consider the possibility of small intestine bleeding. Further capsule endoscopy was performed: small intestinal parasites, hookworms, and chronic inflammation of the small intestinal mucosa. The patient had lived in Hubei for a long time, farmed for a long time, went to the field barefoot, applied manure, and had hookworm susceptibility factors. The hookworm bites the mucosal villi of the small intestine and feeds on blood, mucosal epithelium, and intestinal fluid, and changes the bite site four to six times a day, and secretes anticoagulant substances, causing blood leakage from the adsorption port. Chronic blood loss led to anemia. At this point, the cause of this occult gastrointestinal bleeding was clear – hookworm disease. Supplementation of hematopoietic material and correction of anemia were given, and albendazole 200mg/day*3 days were given, and the patient was discharged on November 22. In recent years, the gastroenterology department of our hospital has been developing and growing, and not only has a certain popularity in Beijing, but also more and more patients from outside Beijing are coming to our hospital, solving practical problems for more patients, which is recognized by the industry and praised by patients.