First, can be used for constipation treatment of many drugs, but most are not suitable for patients with chronic constipation, and not suitable for long-term use. At present, the phenomenon of laxative abuse is more common, resulting in a lot of medical constipation. Commonly used laxatives are the following: 1, stimulant laxatives: in the form of inflammatory mediators by stimulating the colonic submucosal intermuscular plexus, smooth muscle, increase intestinal peristalsis and mucus secretion and defecation. One is anthraquinone class (including rhubarb, senna, aloe vera, Mei Rhamno peel, Frangipani peel, etc.), the second is phenolphthalein class (fruit guide, diacetyl benzidine). Stimulating laxatives can cause severe abdominal cramps, long-term use can cause water, electrolyte disorders and acid-base balance imbalance, can damage the colon mucosa, interosseous nerve and smooth muscle contraction, damage the defecation reflex mechanism, and cause “laxative colonic” to aggravate constipation, coupled with the occurrence of its colonic melanosis. 2, volumetric laxative: this preparation contains cellulose, absorbing water to form a soft gel, so that the stool is easy to discharge, and can stimulate intestinal motility. Mainly wheat bran, corn bran, konjac starch, agar, methyl cellulose, psyllium preparations, Tongtai capsules, etc. are in this category. When taking such preparations must pay attention to drink more water; intestinal stenosis can lead to intestinal blockage, should be used with caution. 3, osmotic laxatives: by increasing the osmotic pressure of intestinal contents, affect the absorption of intestinal water and can absorb water into the intestinal cavity, thus promoting defecation and softening the stool of a class of drugs, almost no side effects. In addition, there are salts and disaccharides such as lactulose, glycerol and sorbitol. Mainly used for acute constipation or intestinal preparation, can not be used for a long time, the diarrhea is intense can cause dehydration. 4, softening laxatives: for surfactants, can make the fat in the stool and water easily mixed, and increase intestinal secretion, such as sodium octobutyrate (calcium), usually taken orally, itself is not absorbed, but can increase the absorption of other substances. Because of hepatotoxicity, can only be applied for 1 to 2 weeks, not suitable for chronic constipation. 5, slippery laxatives: such as paraffin oil. Not digested and absorbed in the intestine, can be wrapped around the fecal mass, so that it is easy to discharge, but also to prevent the absorption of water in the colon, can lubricate the intestinal cavity, soften the stool, the effect occurs 6 to 8 hours after oral intake. Long-term use may hinder the absorption of fat-soluble vitamins A, D, K and calcium and phosphorus. Should not be used with surfactants at the same time, so as not to increase the absorption of mineral oil, the product is also easy to leak from the anus, causing contamination of the mattress and poor taste, only short-term use, not for chronic constipation. 6, colon dynamics: cisapride (Prebios), mosapride, puccapride, methylnaltrexone, zemak, bishacodyl, etc., can increase the release of acetylcholine, stimulate intestinal motility, side effects can increase the absorption of central inhibitory drugs, and its joint application should be cautious. And prolong the cardiac S-T segment, heart disease patients should also be used with caution, as well as the liver and kidney function is reduced. Cisapride, a pro-intestinal motility drug, mainly acts on the upper colon, and has been withdrawn from the market since 2000 due to its uncertain effect and considering its safety.