The main causes of incomplete bowel movement include gastrointestinal dysfunction, bacillary dysentery, ulcerative colitis, colon cancer, and extraintestinal diseases. 1. Gastrointestinal dysfunction: the symptom is caused by eating spicy and greasy stimulating food, cold stomach, abnormal autonomic function and other factors leading to hyperperistalsis of gastrointestinal smooth muscles. 2. Bacterial dysentery: the endotoxin produced by dysentery bacillus after infection of the intestinal tract leads to acute inflammatory reaction of the intestinal mucosa, and the intestinal wall is heavily exudated and congested, so this symptom will appear. 3. Ulcerative colitis: autoimmune dysfunction leads to chronic non-specific inflammatory lesions of the intestinal mucosa, with extensive exudation and ulceration of the intestinal mucosa, so this symptom will appear. 4. Colon cancer: malignant tissue of colon proliferates a lot, leading to dysfunction of normal intestinal mucosa, bleeding, exudation and other lesions, so this symptom will appear. 5. Extra-intestinal diseases: female patients’ pelvic inflammatory lesions can easily involve the neighboring rectum and stimulate the rectal wall, resulting in this symptom. The inability to poop as much as possible is related to a variety of factors, and it is recommended to consult a doctor for a clear diagnosis.