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.
Witchhazel Bark, Hamamelis virginiana. Official in England, Mexico, Spain, and in the eighth U. S. P. The leaves in 12 countries. Active on account of crystalline hamamelitannin and amorphous tannic acid in the bark, and tannic acid in the leaves. Used mostly as the Aqua Hama-Melidis, U. S. P., containing 15% of alcohol. A saturated tincture is better, which may be diluted with 5 to 10 parts of water for external application.
The vessels, especially the veins, of the skin and mucous membranes are constringed by this remedy to a degree not fully explained by its tannin content, even the gastroenteric tract responding somewhat to its influence.
It has never been proven, however, that it possesses any action except that of a tannin-bearer.
But the various forms of tannin vary largely in effectiveness, and it is probable witchhazel offers it in a more than ordinarily available form. Certainly it is an agreeable form in which to use it.
For internal use the fl., in 10- to 30-minim doses, should be used. It will do whatever a good tannin product will do - no more. See "Tannic Acid." It is a superior astringent for internal use, and a valuable astringent and hemostatic externally.
It is a suitable application to a host of minor congestions, sprains, and bruises, and in some cases of pruritus. As a toilet preparation - after shaving, etc. - it possesses value. In passive hemorrhage of the skin and mucous surfaces it often serves well, and it is a palliative application in hemorrhoids, prolapsus ani, and other venous congestions.
The British Pharmacopeia ointment and the B. P. Codex Pasta Hamamelidis, or Witchhazel Snow, are good products. Use hamamelis within its reasonable indications, and it will not disappoint; but remember it is no wonder-worker, as some assert.