Origin. - The resin of the wood of Guaiacum officinale L., or of Guaiacum sanctum L.

Description and Properties. - Irregular masses or subglobular pieces, externally greenish-brown, internally of a glassy luster, and in recent guaiac usually reddish-brown, transparent in thin splinters, fusible, feebly aromatic, the odor becoming stronger upon heating; taste somewhat acrid; powder grayish, turning green on exposure to air. Soluble in potassium or sodium hydrate T. S. and in alcohol, the alcoholic solution being colored blue by the addition of tincture of ferric chloride.

The principal constituents of guaiac resin are - guaiaconic acid, guaiacic acid, guaiaretic acid, and a small amount of gum. It also contains volatile oils. These substances are insoluble in water, but soluble in alkalies.

Dose. - 5-30 grains (0.3-2.0 Gm.) [15 grains (1 Gm.), U. S. P.].

Official Preparations

Tinctura Guaiaci - Tincturae Guaiaci - Tincture of Guaiac. - Dose, 30-60 minims (2.0-4.0 Cc.) [1 fluidram (4 Cc), U. S. P.].

Tinctura Guaiaci Ammoniata - Tincturae Gualaci Ammoniatae - Ammo-niated Tincture of Guaiac. - Dose, 30-60 minims (2.0-4.0 Cc.) [30 minims (2 Cc.), U. S. P.].

Antagonists and Incompatibles. - Spirit of nitrous ether and the mineral acids are incompatible with guaiac. Water is pharma-ceutically incompatible with the tinctures, precipitating the resin.

Synergists. - Many of the diaphoretics and diuretics and the vegetable alteratives aid the action of guaiac.

Physiological Action. - Externally and Locally. - Guaiac is antiseptic, and possesses mildly astringent properties, being used locally as a gargle.

Internally. - The action of guaiac resembles that of the drugs belonging to the volatile oil group. It is a stimulant to the digestive, circulatory, and respiratory systems.

Therapeutics. - Externally and Locally. - Guaiac in some form is an excellent application in follicular tonsillitis, rheumatic pharyngitis, and quinsy. For these cases the emulsion of guaiac serves as an efficient gargle, or the troches of guaiac may be used.

Internally. - From the sixteenth to the eighteenth century guaiac was renowned as a cure for syphilis, having been introduced into Europe from San Domingo. The heroic manner, however, in which the drug was employed rendered the results more injurious than beneficial, so that the guaiac treatment was condemned, one of its most vigorous opponents being Paracelsus, to whom the reintro-duction of mercury for the treatment of syphilis is largely due. The drug possesses properties which render it valuable in chronic muscular rheumatism, neuralgic dysmenorrhea, and atonic amenorrhea.

Guaiac is considered to be an efficient remedy in lumbago and chronic gout. Its most important service, however, in therapeutics is in the treatment of quinsy. It is doubtful whether there is any drug which will modify the course of this disease or abort an attack of tonsillitis so readily as this medicine. The tincture of guaiac is the preparation usually employed for this purpose, 1/2 fluidrachm (2.0 Cc.) being given in the form of an emulsion every three or four hours.

Contraindications. - There are no marked contraindications to its use.

Administration. - The tinctures are very acrid and disagreeable to the taste, and should be given in the form of an emulsion. The emulsion of guaiac, a formula for which is given in the Dispensatories, is not unpleasant, and is altogether the best liquid preparation to give.

The lozenges of guaiac, allowed to dissolve slowly in the mouth, serve as an agreeable and efficient method of medicating the throat with this drug.