Guaiacum denotes a genus of the zygomatic family (Zygophyllaceae). It contains six to eight tree species from tropical and subtropical America. Guaiacum species are trees or shrubs with very hard, resin-rich wood. There are six to eight species in the genus of guaiac trees (Guaiacum) in tropical and warmer America: Guaiacum angustifolium – Mexico and Texas; Guaiacum coulteri – Mexico; Guaiacum unijungum – Baja California in Mexico; Guaiacum officinale L. – Antilles and the north coast of South America. French wood tree, or pockwood tree, is a 12 m high, evergreen tree with a spreading crown, opposite, two-, rarely three-year-old leaves, oval, leafless leaflets, long-stemmed, blue flowers and two-sided capsule. The wood is very heavy (density about 1.2 g / cm3), firm, hard, brittle, splits heavily and irregularly, is dark greenish brown, surrounded by light yellow sapwood and sharply demarcated from it. In Mayan culture, decoctions of wood were used to treat the venereal disease syphilis. Guaiacum officinale and Guaiacum sanctum supply the guaiac wood (French wood, pockwood) and the guaiac resin obtained from it.
The word guaiac is of West Indian origin. The Latin name Lignum vitae refers to the supposed healing and life-extending properties of this wood, which was famous in the 18th century. The Spaniards got to know the use of the wood from the locals of Santo Domingos. The first records of therapy for syphilis can be found in the work “Summario de la natural y General de las Indias” (1526) by Gonzalo Fernández de Oviedo y Valdez (1478–1557). The German term “pockholz” came about because the shavings of the guaiac tree contain oils that were previously used as medicines in the medically unproven belief that extracts of the wood were able to cure smallpox. Pockholz was used as one of the hardest woods ever for centuries – for shipbuilding – for belaying pins and deadeyes, for the production of axle bearings (axis to the ship’s propeller, hydropower turbine), press rollers, cone balls, mortar and pestles, the hammer for caulking, etc.