Botanical name: 

The root of Ipomaea jalapa.—Mexico.

Preparations.—The powdered root. A tincture. The resin. Compound powder of Jalap.

Dose.—Of the powder, grs. x. to grs. xxx. Of the tincture, gtt. x. to ʒss. Of the resin, gr. j. to grs. x. Of the compound powder, ʒss. to ʒij.

Therapeutic Action.—Jalap, in powder and in its resin, acts efficiently upon the bowels, causing nausea, sometimes vomiting and copious alvine evacuations, and if the dose is large, violent hypercatharsis and after-griping. Dr. Christison says, that severe and even dangerous effects have followed its use. If it ever acts dangerously, when administered in ordinary doses, it must be in rare cases, and when other agents of this class, though usually mild in their effects, would produce like results. It is a very safe and convenient cathartic.

Jalap is an active hydragogue cathartic, operating to some extent upon every portion of the alimentary canal, but its influence is mostly expended upon the small intestines. It stimulates the intestinal mucous exhalants, and causes copious watery discharges. As a cathartic, we have but few agents that act so briskly, so kindly, and yet so certainly, safely, and thoroughly.

As a detergent, deobstruent, and hydragogue cathartic, it is prescribed with great advantage in febrile and inflammatory diseases. As a derivative, it is among the best of this class of agents, and is, therefore, employed in encephalitis, and other diseases in which this derivative action is desirable.

It is very effectual in cleansing the alimentary canal, removing torpor, congestions, relieving vascular repletion, equalizing the circulation, and subduing organic excitement. If given in combination with the bitartrate of potash, it forms a very effectual refrigerant and antiphlogistic cathartic. The same combination is very valuable in dropsy. It removes large portions of the serum of the blood, which causes a rapid absorption of the effused fluid to replenish the waste. It may also be combined with the podophyllum or podophyllin, or small portions of the Elaterium in the same disease. Two or three grains of Ipecacuanha added to fifteen or twenty grains of Jalap, enhances its cathartic powers, and causes it to operate much more efficiently than a much larger portion of the Jalap alone.

The American Eclectic Materia Medica and Therapeutics, 1898, was written by John M. Scudder, M.D.