About Guaiacum officinale L.
Guaiacum officinale L. is a very slow-growing small tree. It reaches roughly 10 meters (33 feet) in height, with a trunk diameter of 60 centimeters (24 inches). Across most of its native range, this tree is essentially evergreen. Its leaves are compound, measuring between 2.5 and 3 centimeters (0.98 to 1.18 inches) long, and 2 centimeters (0.79 inches) wide. Its blue flowers have five petals, and the tree produces bright-yellow-orange fruit with red flesh and black seeds. Guaiacum officinale is one of just two species that produce true lignum vitae; the other species is Guaiacum sanctum. Guaiac, a natural resin extracted from the wood of this tree, is a colorless compound. It turns blue when it comes into contact with substances that have peroxidase activity, after being exposed to hydrogen peroxide. Guaiac cards are impregnated with this resin, and they are used to test for blood in human stool. The heme portion of hemoglobin has peroxidase activity. If blood is present in the stool, this heme will catalyze the oxidation of guaiaconic acid once hydrogen peroxide is applied to the Guaiac card.
