Hemorrhoids are divided into internal, external, and mixed hemorrhoids. Internal hemorrhoids are pathological changes and/or abnormal displacement of the vascular cushions of the anal canal. External hemorrhoids are pathologic dilatation and thrombosis of the subepidermal venous plexus of the inferior rectal vein in the distal aspect of the dentate line. Mixed hemorrhoids are the fusion of the internal hemorrhoidal venous plexus and the corresponding external hemorrhoidal venous plexus. Its pathogenic factors are: 1, occupational factors: long standing, sedentary, squatting, long-term weight-bearing operation, affecting venous return, so that the pelvic blood return slow, resulting in hemorrhoidal venous stasis and expansion, anal cushion hyperplasia and hypertrophy of hemorrhoids into the hemorrhoids. 2, dietary factors: long-term overeating pungent and dry, excessive alcohol consumption, low-fiber diet, etc. may stimulate the anus and rectum congestion, prompting venous plexus flexion and dilatation of the hemorrhoids. 3, disease factors: chronic diarrhea (colorectal inflammation, bacillary dysentery, dyspepsia, etc.), chronic constipation, pregnancy, childbirth, increased abdominal pressure (prostate hypertrophy, emphysema, pulmonary heart disease, etc.), portal hypertension (cirrhosis, congestive heart failure), etc., may be so that the anorectal blood congestion or blood reflux obstacles, blood stagnation leads to increased capillary permeability, vascular plexus tortuous expansion, anal cushion hyperplasia and hypertrophy. 4, anal canal defect: anal canal defect affects anal closure, the local mucosal tissue will compensate to fill the defect, gradually proliferation hypertrophy prolapse, the formation of hemorrhoids. 5, genetic factors: hemorrhoidal vein wall congenital weakness, prone to hemorrhoidal venous plexus flexion expansion, but this view is quite controversial.