This section is from the book "Materia Medica And Therapeutics - Vegetable Kingdom", by Charles D. F. Phillips. Also available from Amazon: Materia Medica And Therapeutics: Vegetable Kingdom.
Active Ingredients. - Logwood contains haematoxylin orhaema-tine, C16H14O6, which substance is sometimes found crystallized in the crevices; tannin also, resin, and the ordinary constituents of wood in general. The taste of this substance is slightly bitter, acrid, and astringent; it is soluble in alcohol and ether, and slightly so in water. Acted upon by alkalies, it gives a red or purplish color; by acids, a yellowish or red one. The coloring and the astringent principles of the wood itself are dissolved out both by water and by alcohol; the solutions are deepened in color by alkalies, and are rendered slightly turbid by acids.
Physiological Action. - Logwood, in decoction, is a mild astringent. It does not constipate, nor does it disorder the bowels, and its color can be detected both in the urine and the stools. The use of this medicine has been known to produce phlebitis.
Therapeutic Action. - Logwood is usefully administered in dysenteries and diarrhoeas of long standing, and is specially adapted to diarrhoea in children. It is also employed as an astringent in haemorrhages from the lungs, the uterus, and the bowels, and has been found efficient in leucorrhoea. Dr. Percival used logwood to check profuse perspiration in phthisis.
Preparations and Dose. - Extract. Haematoxvli, err. v. - xx. (.30 - 1.25). Decoct. Haematox.,
- ij. (30. - 60.).