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laxative

laxative, drug or other substance used to stimulate the action of the intestines in eliminating waste from the body. The term laxative usually refers to a mild-acting substance; substances of increasingly drastic action are known as cathartics, purgatives, hydrogogues, and drastics, respectively. Laxatives or cathartics fall into three general categories: irritants that stimulate the muscular action of the intestines (cascara, phenolphthalein, senna); compounds that increase the amount of bulk in the intestines either by withdrawing water from the body (salines such as Epsom salts, citrate of magnesia) or by increasing the bulk when combined with fluids (agar-agar, bran, the various cellulose substances); and lubricants such as mineral oil, which ease the passage of waste and counteract excessive drying of the intestinal contents. Frequent or regular use of cathartics may seriously disrupt the natural digestive processes. When food and even waste products are forced out of the intestinal tract too rapidly, the body is deprived of vital substances, including the nutrients absorbed in the small intestine and the water, vitamins, and minerals extracted from the waste matter in the large intestine. Vitamins A and D, which are soluble in oil, are removed from the body even when the least irritating laxative, mineral oil, is taken. In addition to disrupting digestive and nutritional processes, laxatives reinforce the condition they are intended to overcome. When the intestines are purged, it may be several days before they can fill again with sufficient waste to induce natural elimination. The harm can be perpetuated by frequent use aimed at forcing daily elimination. The response to laxatives is soon lessened, so that larger and more frequent doses may become necessary. Laxatives should be avoided especially when there is abdominal pain. An inflamed appendix may rupture after the use of a laxative. See constipation.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

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