Guaiacum wood was first introduced into Europe by the Spaniards in 1508, and Nicolaus Poll, writing in 1517 (see Luisinus, _De morbo gallico_, p. 210, Ven., 1566), states that some three thousand persons in Spain had already been restored to health by it. The virtues of the resin, however, were not known until a later period, and in Thomas Paynel's translation (_Of the Wood called Guaiacum_, &c., p. 9, ed. of 1540) of Ulrich von Hutten's treatise _De morbi gallici curatione per administrationem ligni guaiaci_ (1519) we read of the wood: "There followeth fro it, whan it bourneth a gomme, which we yet knowe not, for what pourpose it serueth." Fluckiger and Hanbury (_Pharmacographia_, p. 95) state that the first edition of the _London Pharmacopoeia_ in which they find the resin mentioned is that of 1677. The decoction of the wood was administered in gout, the stone, palsy, leprosy, dropsy, epilepsy, and other diseases, but principally in the "morbus gallicus," or syphilis, for which it was reckoned a certain specific, insomuch that at first "the physitions wolde not allowe it, perceyuynge that theyr profite wolde decay therby" (Paynel, _op. cit._ p. 8). Minute instructions are given in old works as to the mode of administering guaiacum. The patient was confined in a closed and heated chamber, was placed on the lowest possible diet, and, after liberal purgation, was made twice a day to drink a milk-warm decoction of the wood. The use of salt was specially to be avoided. A decoction of 1 lb. of guaiacum was held to be sufficient for the four first days of the treatment. The earlier opinions as to the efficacy of guaiacum came to be much modified in the course of time, and Dr Pearson (_Observations on the Effects of Various Articles of the Mat. Med. in the Cure of Lues Venerea_, c. i., 2nd ed., 1807) says:--"I never saw one single instance in which the powers of this medicine eradicated the venereal virus." He found its beneficial effects to be most marked in cases of secondary symptoms. Guaiacum resin is given medicinally in doses of 5-15 grains. Its important preparations in the British Pharmacopoeia are the _mistura guiaci_ (dose 1/2-1 oz.), the ammoniated tincture of guaiacum (dose 1/2-1 drachm), in which the resin is dissolved by means of ammonia, and the trochiscus or lozenge, containing 3 grains of the resin. This lozenge is undoubtedly of value when given early in cases of sore throat, especially of rheumatic origin. Powdered guaiacum is also used. Guaiacum resin differs pharmacologically from other resins in being less irritant, so that it is absorbed from the bowel and exerts remote stimulant actions, notably upon the skin and kidneys. It affects the bronchi but slightly, since it contains no volatile oil.