purgative

(also, depending on the substance used, laxative, cathartic, or aperient), a medicinal substance that increases the frequency and fluidity of stool, thus normalizing intestinal function in cases of constipation. In chemical composition, purgatives may be inorganic compounds, for example, such salts of alkali and alkaline-earth metals as sodium sulfate, Carlsbad salt artificial, and magnesium sulfate. They may also be organic compounds, for example, acids and such oils as mineral and castor oils. Some vegetation can also serve as purgatives, for example, powder of rhubarb.

The mechanism of purgative action varies. Rhubarb and phonolphthalein stimulate the chemoreceptors of the intestinal mucosa, and mineral and vegetable oils facilitate the movement of intestinal contents. Salt purgatives inhibit the absorption of water in the intestine, which increases the volume of intestinal contents and results in intensified peristalsis. The use of mineral waters as purgatives is based on the action of salts; mineral waters include the Slavianov, Morshin, Batalin, and the Izhevsk mineral waters. Closely related to salts in their action are substances that swell in water, such as linseed and sea kale.

Purgatives are used in cases of constipation and to remove poisons and poor-quality food products from the intestine (salt purgatives). The administration of purgatives is contraindi-cated in cases of intestinal inflammatory processes or pregnancy.