This section is from the book "A Practitioner's Handbook Of Materia Medica And Therapeutics", by Thos. S. Blair. Also available from Amazon: A Practitioner's handbook of Materia Medica and Therapeutics.
Quillaja, Soap Bark, is used pharmaceutically, and the tincture, in 15 I. doses, is classed as expectorant. It is expectorant, but is altogether a minor remedy. Two or 3 I. doses are large enough, and exercise some influence in the early stages of coryza and catarrhal sore throat.