Many people have this question: Is it normal to have a bowel movement every day? Is it constipation if you don’t have a bowel movement for more than three days? In fact, under normal circumstances, if the stool is not dry or hard, and defecation is not difficult, then the frequency of defecation is normal from three times a day to once every three days. Constipation mainly refers to the difficulty in the process of defecation – straining to defecate, not smooth, taking a long time to defecate or feeling unclean, etc. It does not only depend on the frequency of defecation. Even if it is three times a day, as long as the bowel movement is difficult and obstructive, it is also called constipation. However, if you do not have a bowel movement for more than three consecutive days, you should pay attention to whether you have constipation. Generally speaking, if you have constipation for six consecutive months, you are considered to have chronic constipation. What are the types of chronic constipation? In terms of etiology, there are two types: organic constipation and functional constipation. 1, organic constipation: refers to constipation caused by some diseases, such as colon tumors, inflammation, connective tissue disease, diabetes, thyroid disease and structural changes in the intestine may cause constipation. Before diagnosing functional constipation, it is this type of problem that must be ruled out. 2, functional constipation: refers to the exclusion of disease, the etiology of a type of constipation is not clear, the general examination can not find structural and systemic problems. Most patients with chronic constipation belong to functional constipation. Functional constipation includes four types in terms of pathophysiological mechanisms: (1) slow-transmission constipation: slow-transmission constipation is predominantly in the elderly (also in young people), which is characterized by a lack of colonic dynamics, slow movement of the colon, and slow transport of “cargo”, resulting in slow passage of colonic contents through the colon. The most important characteristic of these patients is that they do not have a bowel movement, they have a bowel movement once every many days, some of them only have a bowel movement once every seven or eight days, and in severe cases, they cannot even have a bowel movement without medication! On the other hand, the stools of these patients are particularly dry. Since the intestinal contents stay in the intestinal tract for a long time, the water is absorbed by the large intestine, so the final stool will be very dry, and there may even be a hard stool like sheep feces. The cause of slow-transmission constipation may be a problem with the muscles in the colon or with the regulation of the nerves associated with colon motility, which leads to a decrease in colon motility. (2) Exit-obstruction constipation: Patients with exit-obstruction constipation have normal colonic motility and the speed of food residues passing through the colon is not slow, but the stool is blocked at the anal opening, so it cannot be excreted. The characteristic of this type of patients is that even if the stool is not dry (or even thin), they have obvious difficulty in defecation: they have the urge to defecate, but they cannot defecate no matter how hard they try, and some of them even use their hands to pick at the stool to help defecate. The cause of exit obstruction type constipation is mainly due to certain functional problems in the process of defecation, such as inability to open the anal sphincter, rectal protrusion, rectal intussusception, etc., which leads to stool blocked in the anal opening, can not be defecated. (3) Mixed constipation: Patients with mixed constipation have both slow colonic motility and outlet disorders, and the symptoms of this type of constipation are more serious and the treatment is more complicated. (4) Normal transmission constipation: Patients with normal transmission constipation are relatively rare. These patients have normal colon motility, food residues can pass through the colon normally, and there is no obvious obstruction to the defecation process, but they just cannot pass out. These patients may have some mental or psychological problems (such as prolonged depression, agitation, insomnia, etc.), which may lead to difficulty in defecation. Another type of functional constipation is the constipated type of irritable bowel syndrome, in which patients have abdominal pain or discomfort in addition to the problem of defecation, and these abdominal symptoms can be alleviated or relieved after defecation. In contrast, patients with functional constipation usually have no abdominal symptoms. The inner wall of the large intestine is covered with the colonic mucosa, and there are many intestinal glands distributed on the mucosa. The intestinal glands can secrete colonic fluid, which is like a lubricant in the intestine. On the one hand, the colonic fluid can separate the colonic mucosa from food residues and other contents, and prevent some hard residues and metal instruments from damaging the colonic mucosa and lining. On the other hand, colonic fluid can reduce the friction between the mucous membrane and food residues, so that the residues can pass through the large intestine more smoothly and be excreted from the body.