Normal anus is the end of the digestive tract to the body of the opening, usually tightly closed, was before and after the longitudinal fissure, defecation when the expansion of the round, about 2-3 cm in diameter. the anal part of the skin is black, there are rows of sacs, sweat glands and sebaceous glands, often because of the contraction of the muscles to form a number of radial folds. Hemorrhoids refers to the lower rectum and the anal canal wall of the venous plexus expansion, curved bulging, and the formation of venous masses, most of the benign disease, usually not cancerous. Hemorrhoids can be divided into three types: internal hemorrhoids, external hemorrhoids, and mixed hemorrhoids. Internal hemorrhoids are called internal hemorrhoids if they are within the dentate line, and external hemorrhoids are called external hemorrhoids if they are outside the dentate line or have prolapsed outside the anus. If there are hemorrhoids protruding from both above and below the dentate line, they are called mixed hemorrhoids.