This section is from the book "Materia Medica And Therapeutics: An Introduction to the National Treatment of Disease", by John Mitchell Bruce. Also available from Amazon: The pharmacology and therapeutics of the materia medica.
Resin of Jalap.
Source.-Made by precipitating a tincture of jalap in water.
Characters.-Dark-brown opaque fragments, translucent at the edges; brittle, with a resinous fracture; with a sweetish acrid taste; readily soluble in spirit, insoluble in water.
Substance resembling Resin of Jalap: Aloes, which is hitter. Dose, 2 to 5 gr.
Preparations of Jalapa:
Extractum Jalapae. Spirituous and aqueous. 2 in 1. Dose,
5 to 15 gr.
Pulvis Jalapae Compositus. Jalap. 5; Acid Tartrate of Potash, 9 ; Ginger, 1. Dose, 20 to 60 gr.
Tinctura Jalapae. 1 in 8. Dose, 1/2 to 2 fl.dr.
Jalajoe Resina is contained in Pilula Scammonii Composita.
The action of jalap closely resembles that of scammony, but it is less irritant or likely to gripe. Like it, jalap does not purge unless in the presence of the duodenal fluids; it is also a powerful stimulant of the intestinal secretion, less so of the bile. Small doses produce a laxative effect; large doses act within two hours, causing several watery stools, and some pain, unless combined with carminatives.
Jalap is extensively used in the form of the Compound Powder, as a hydragogue purgative to drain off water by the bowel in dropsy, and occasionally as an ordinary smart purgative. The resin in small doses may be used in laxative pills for habitual constipation. As an anthelmintic, jalap occurs in Pulvis Scammonii Compositus. This drug must be avoided when the alimentary canal is inflamed or irritable.