The emptying, cleansing, purging or evacuation of the bowels (intestines). A cathartic or purgative is an agent that causes catharsis and is more commonly known as a laxative (a cathartic taken to relieve constipation). Further Information: Cathartics may be broken down into several different categories: Bulk cathartics stimulate evacuation of the bowel by increasing the bulk of the feces (stool). Examples include psyllium husk (the active ingredient in Metamucil), methylcellulose (the active ingredient in Citrucel) and dietary fiber such as wheat and oat bran. Lubricant or emollient cathartics soften the feces and reduce friction between the stool and the intestinal wall. Examples include mineral oil, docusate sodium (marketed as Surfak and Colace), and glycerin (as suppositories). Osmotic cathartics increases the water content and weight of the feces using the principle of osmosis. These can be further subdivided into two categories: (a) Saline cathartics - Examples include magnesium citrate, magnesium sulfate, sodium sulfate, and magnesium hydroxide (Phillips Milk of Magnesia. (b) Disaccharides - An example is sorbitol which increases stool bulk through fermentation in the bowel. Free tip: don't eat too much sugarless candy containing this artificial sweetner. (c) Stimulant cathartics cause wavelike muscular contractions around the intestines (peristalsis) that expel the contents. A common example used to be phenolphthalein, but this was banned for use as a laxative in 1997 because of the remote possibility that it was cancer-causing. A currently available example is bisacodyl (the active ingredient in Dulcolax). Stimulants are much faster acting, harsher, and more likely to cause laxative dependency than the other types of laxatives. (d) Combination agents work through one or more of the above mechanisms. MSDS Relevance: You will generally find the term cathartic or catharsis on an MSDS in reference to: (1) As a first aid measure to treat ingestion of the substance. Cathartics can decrease the absorption of substances in the gastrointestinal tract by accelerating the expulsion of the poison from the body. This may be a preferred method when the material involved is a caustic - for example, instead of inducing vomiting which would cause additional damage to the esophagus and throat. (2) The decision to utilize a cathartic in a poisoning situation should be made by a qualified medical professional only. There are other ways of reducing the absorption of toxic materials in the body; See: The additional terms at the bottom of this page and Further Reading below. (3) As a symptom of exposure, usually through ingestion of the material. See also: Activated Charcoal, Antidote, Emesis, Gastric, Poison