What are hemorrhoids?” Such a seemingly simple and basic question can be difficult to answer even for specialists who have been working in the field of anorectal medicine for many years, because what exactly are hemorrhoids? It is not completely clear that there is a unified understanding, and there is still controversy. There are more than ten theories about what hemorrhoids are, such as varicose veins theory, vascular proliferation theory, infection theory, pressure gradient change theory, hemorrhoidal hernia formation theory, inferior rectal artery branching theory, anal canal stenosis theory, erectile tissue theory, sinus venous theory, rectal canal decline theory, rectal canal force imbalance theory, metaplasia theory, anal sphincter dysfunction theory, hemorrhoidal venous pump function theory, and so on. Each of these theories has more or less supporters and can explain one or two aspects of hemorrhoids, but they do not fully explain “what are hemorrhoids?” I’m going to explain it thoroughly. Now I will introduce you to the DD theory, which has been endorsed by a relatively large number of scholars and has a more consistent understanding of the explanation of hemorrhoids, as an answer to the question “What are hemorrhoids? The answer to this question. The anal cushion is a normal tissue structure in the lower part of the human rectum, consisting of a number of veins, muscles and fibers that assist in the function of anal closure, and is a very fine receptor that can tell whether the stool arriving at the anus is hard, soft, thin or no stool at all, only gas (farts). She is held in place by a muscle that is rich in blood vessels in the lower rectum. As we age, and in response to various stimuli, this muscle gradually ages and becomes less and less elastic, or even breaks, causing the anal cushion tissue to move down, and the hemorrhoidal plexus inside gradually becomes tortuous, dilated and stagnant, thus forming hemorrhoids. Hemorrhoids are divided into internal, external and mixed hemorrhoids depending on where they occur.