Constipation makes people tremble at the mention of colonoscopy. In fact, after the patient goes to the doctor, the doctor can judge and analyze the cause of constipation according to your secret history, degree, constipation nature, color, shape and accompanying symptoms of stool, and then consider whether it is necessary to do this examination. Explore the reasons: bad living habits, eating less or eating too thin food, lack of fiber. Drink too little water or eat too much spicy food and drink too much wine. Too little exercise or sedentary. Normal defecation habits are too few or the regularity of "going out" is too neglected. Reason clue 2: The digestive tract itself is caused by colon stenosis, intestinal tumor, intussusception torsion, anastomotic stenosis, parasitic diseases, inflammatory growth, adhesion, granuloma of venereal diseases, etc. Colon neuromuscular diseases: congenital megacolon, colonic weakness, pseudointestinal obstruction, diverticulosis, irritable bowel syndrome, intestinal tuberculosis, etc. Anorectal lesions: perianal lesions such as hemorrhoids, anal sinusitis, perianal abscess, anal fissure, rectocele, intussusception in rectum, internal sphincter achalasia, pelvic floor spasm, perineal descent, puborectalis hypertrophy, etc. Etiological clue 3: Systemic diseases cause endocrine and metabolic diseases, such as hypokalemia, hypercalcemia, hypothyroidism, diabetes, diabetes insipidus dehydration, pituitary hypofunction, neuroblastoma, lead poisoning, porphyria and so on. Emaciation, malnutrition, chronic emphysema and diaphragmatic paralysis caused by long-term chronic wasting diseases; Abdominal muscle failure caused by obesity, pregnancy, long-term bed rest, huge intra-abdominal tumor and ascites; Female prolificacy, birth injury and surgical injury lead to pelvic floor muscle failure; And intestinal smooth muscle contraction is weak, leading to flaccid constipation. Nervous system diseases: such as Parkinson's disease, brain tumor, cerebrovascular disorder, encephalitis and other central nervous system diseases, cauda equina neuropathy, spinal tuberculosis, multiple sclerosis, myelitis and other spinal cord tumor or injuries; Lumbosacral nerve injury or loss: peripheral nerve injuries such as pelvic nerve resection and polyradiculitis can cause sensory impulse afferent disorder, that is, defecation reflex arc is blocked and constipation occurs. Mental factors and mental illness: mental stress can elevate the anus, which is enhanced by sphincter reflex activity. Long-term bad mood or excessive mental stress leads to anal sphincter achalasia, which leads to functional constipation. Mental depression, personality anxiety, hypochondria, hysteria, anorexia nervosa, neuropathy, etc. Make the autonomic nervous system out of balance, increase the excitability of sympathetic nerve, inhibit intestinal movement and secretion, hinder defecation reflex and produce constipation. Intra-abdominal diseases: extraintestinal compressive obstruction, such as ovarian cyst, hysteromyoma, intra-abdominal tumor, pelvic floor hernia, ascites, etc. Compression of intestinal and abdominal inflammation, such as appendicitis, pancreatitis, cholecystitis and peritonitis; Visceral pain diseases, such as gallstones, kidney calculi, visceral ptosis, etc. It can inhibit constipation caused by intestinal movement through reflection. Reasons and clues to explore four kinds of drugs: long-term use of laxatives and laxatives increases the threshold of defecation, and the intestine loses the function of judging defecation by itself, resulting in conscious inhibition of defecation. Anesthesia and anesthetic help relax muscles. Iatrogenic causes: constipation caused by intestinal peristalsis, constipation caused by intestinal smooth muscle dysfunction caused by commonly used codeine, antidepressants, anticonvulsants, iron agents and anticholinergic drugs, in addition to painkillers, antacids, barium sulfate, bismuth, diuretics, antihypertensive drugs, monoamine oxidase, ganglion blockers, neurotoxic chemotherapy drugs for chemical poisoning (including arsenic, lead and mercury), etc. During hospitalization, bedridden and bedridden, it is easy to cause defecation difficulties due to the increase of abdominal pressure required for bedridden defecation. In addition, there are various causes of constipation, such as women, the elderly, children with special physiological conditions and so on. If the doctor investigates and finds out the causes of constipation one by one, you can consider whether colonoscopy is needed.