This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
Soap Bark, Quillaja Saponaria. Official in several countries and in the U. S. P. VIII. Q. smegma-dermis is official in France. Quillaja is allied to senega, but the sapotoxin therein makes it too irritant and toxic for internal use; but an infusion makes a good stimulant application for old ulcers and is used as a cleansing agent.