Constipation refers to difficulty or effort in defecation, poor bowel movement, reduced frequency of defecation, and low volume of dry stool. The common causes of constipation are: 1. Colon and anal diseases: ① congenital diseases, such as congenital megacolon; ② intestinal stenosis, such as inflammatory bowel disease, stenosis after late trauma and intestinal anastomosis, intestinal stenosis due to tumor and its metastasis; ③ outlet obstruction, such as pelvic floor dislaxation, rectal folding, perineal descent, rectal protrusion, etc.; ④ anal canal and perianal diseases, such as anal fissure, hemorrhoids, etc.; ⑤ other, such as irritable bowel syndrome, etc. 2, extra-intestinal diseases: ① neurological and psychiatric diseases, such as cerebral infarction, cerebral atrophy, paraplegia, depression, anorexia, etc.; ② endocrine and metabolic diseases, such as hypothyroidism, diabetes, lead poisoning, vitamin B? deficiency; ③ pelvic diseases, such as endometriosis, etc.; ④ pharmacogenic diseases, such as stimulant laxatives (phenolphthalein, rhubarb, senna) can cause secondary constipation when taken in large quantities for a long time, morphine, narcotics, anticholinergics, etc. Narcotics, anticholinergics, calcium channel blockers, antidepressants, etc. can cause a decline in intestinal stress; ⑤ myopathy, such as dermatomyositis, scleroderma, etc. 3, bad habits: ① too little food, fine food, too many calories of food, few vegetables and fruits, little water, insufficient stimulation of the intestine; ② less exercise, sedentary, bed-ridden, so that the intestinal power is weakened; ③ bad defecation habits. 4, social and psychological factors: ① interpersonal tension, family disharmony, mood in a long-term depressed state, can make the autonomic nervous disorder, causing intestinal motility inhibition or hyperactivity; ② life pattern changes, such as travel, hospitalization, the impact of unexpected events, etc., can lead to changes in the regularity of defecation. Therefore, there are many possible causes of constipation, which can only be determined according to the patient’s condition and relevant examinations. In addition, the causes of constipation can be mild or severe, so patients should pay attention to them and go to the hospital for investigation as soon as possible to avoid delaying the condition.