1, chronic diseases: such as prolonged malnutrition, physical weakness, resulting in anal sphincter relaxation and weakness. Chronic bronchitis, emphysema, by coughing and wheezing constitute a rise in abdominal pressure, pelvic stasis. Slow hepatitis, liver stiffness, diarrhea, colitis, etc. are all triggers for the onset of anal disease. 2, bad defecation habits: squatting position to read a book and newspaper when going to the toilet, so that the defecation time is prolonged, causing stasis of blood in the anorectum and cause disease. Excessive force when fecal, some people regardless of fecal sensation is not intense, blindly and constantly fierce struggle, can only make the rectum anus and pelvic floor muscles increase unnecessary burden and partial stasis of blood, resulting in the onset of disease. 3, fecal abnormalities: diarrhea and fecal constipation are important causes of hemorrhoids. The most important source of disaster is the constipation of feces, the rectum for a long time to stay toxic substances can not only cause rectal malignancy, and fecal accumulation, affecting blood circulation. 4, dietary reasons: the quality of food coarse, vegetable varieties and the amount of change, the amount of protein, fat, starch, fiber and other content, water intake, can directly affect the stool composition, resulting in anorectal disease. 5, physiological reasons: colon, rectum for the transport of food residues, the primary organ for the retention of feces, and food by the body after differentiation and absorption, residues often with a lot of harmful substances, long stay in the colon cecum, can cause tumors. 6, embryonic development abnormal causes: development process abnormal, can be in the anorectal part of many congenital anorectal diseases, such as congenital anus, congenital rectovaginal fistula, congenital giant colon, etc..