For the 90-year-old man 20 days without bowel movement will be dangerous, fecal stasis in the intestinal tract is easy to form fecal stone obstruction, resulting in intestinal obstruction, in addition to easy to induce cardiovascular and cerebrovascular diseases. 1. Intestinal obstruction: when the elderly do not defecate for 20 days, if there is abdominal distension, abdominal pain and exhaust stop, accompanied by nausea, vomiting and other symptoms, this time, we should be highly alert to the occurrence of intestinal obstruction, intestinal obstruction for the surgical emergency abdomen, for the elderly have a high degree of risk, if the above symptoms, should immediately go to the hospital, so as not to delay the condition. 2. Cardiovascular diseases: when the elderly do not defecate for 20 days, they usually exert themselves excessively during defecation, which can easily induce cardiovascular diseases, such as coronary syndromes, hypertensive crises, as well as cerebral hemorrhage, cerebral infarction, or even myocardial infarction, etc. Therefore, if the old man does not have defecation for a long time, it is recommended that he go to the hospital as soon as possible to find out the cause of the disease, and then carry out targeted treatment under the direction of the doctor.