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.
Logwood, Haematoxylon campeachianum. Official in Austria, England, Mexico, and in the Eighth U. S. P. An astringent and feeble antiseptic. It is one of the tannin-bearers and one of the more agreeable to take; but it has the disadvantage of staining fabrics which are in contact with discharges from patients taking the drug. It is used successfully in tuberculous diarrhea and other relaxed conditions of the bowels.
The decoction is used in doses of one or two ounces; the extract, 10 to 30 grains; fluidextract not on the market. See "Tannic Acid."