Multi-organ insufficiency syndrome in the elderly is an important cause of death in elderly patients with critical illnesses. Impairment of body functions leads to a decline in body functions, and the body’s ability to fight infections decreases. Multi-organ insufficiency syndrome in the elderly is a manifestation of decreased ability to fight infections. What are the tests for decreased resistance to infection? 1. Routine blood tests: Hemoglobin and hematocrit may be decreased. 2, Stool routine: positive stool occult blood test. 3.Fiber gastroscopy: it has special importance. Most scattered pale spots are seen on the proximal mucosa of the stomach in the early stage, and multiple superficial red erosion spots are visible after 24-36h, and ulcers can appear later, even black, and some of them show active bleeding. 4.Selective arteriography: The site and extent of bleeding can be determined, and drugs can be injected via catheter to stop the bleeding. Ageing factors alone can make the function of the organs of the elderly generally decline by 1/3, the chronic diseases suffered by further decline in the function of the affected organs, according to statistics, China’s MODSE, per capita suffering from 2.4 important chronic diseases, more than 9, these organs once stimulated by the triggering factors, its function will deteriorate sharply, a chain reaction occurs, leading to multi-organ failure.