The absence of bowel movements may be caused by bad living habits, colorectal and anal diseases, and extraintestinal diseases. 1. Bad life habits: usually due to various reasons such as weight loss, eating too little, and unhealthy dietary habits such as low intake of vegetables and fruits, low drinking water, too little exercise as well as poor defecation habits and laxative abuse and other factors, resulting in the patient’s lack of bowel movement. 2. Colon and anal diseases: such as irritable bowel syndrome, inflammatory bowel disease, colon tumor, anal fissure, hemorrhoids and other anal diseases, may also lead to patients without stool. 3. Extra-intestinal diseases: neuropsychiatric diseases such as cerebral atrophy and depression, endocrine diseases such as hypothyroidism and diabetes, and pelvic diseases such as endometriosis and prostate cancer may also lead to the absence of bowel movement. There may be other reasons why patients do not have bowel movements, and it is recommended to go to the hospital in time for consultation and active treatment to avoid delaying the condition.