Boldo Leaf

Boldo Leaf oil is an essential oil that is thought to help with gallstones, the liver, and inflammation of the urinary system. It is thought to be toxic to humans and is therefore not typically used therapeutically.

Plant
The Peumus Boldus plant is a tree that produces small fruits that look like berries and are typically yellow-green. The tree also has flowers, and each tree either produces male or female flowers, not both. The boldo leaf contains around 2-4% of oil. The main constituents of Boldo leaf are alkaloids, flavonoids, colatile oil, coumarin, resin, and tannin.

Toxicity
Ascaridole, one of the main volatile oils (40%) found in Boldo leaf, is thought to be toxic to humans. Some potential symptoms of exposure to ascaridole include skin and mucus membrane irritation, temporary deafness and blindness, vomiting, vertigo, and a litany of other issues. If there is a sustained release of ascaridole, potential complications such as convulsions and coma can occur. After long-term use, issues such as pulmonary edema, jaundice, blood in urine, and many other issues may appear. Ascaridole has even been proposed as a possible pesticide for Japanese beetle larvae in the form of wormseed oil. Overall, boldo leaf oil shouldn't be used internally or externally, partly due to the inherent toxicity of some of its components, and partly because of the lack of research into the toxicity of the oil itself in totality.

History
Tha effects of boldo leaf were discovered when grazing sheep consumed the leaves of the boldo plant and no longer suffered from constipation or liver issues. In Chile it is used to get rid of intestinal worms, and has a reputation for being a diuretic and a laxative. It is thought to stimulate the secretion of bile, which can assist in the digestion of fat. In Germany, The German Commission E approved it for usage as treatment for dyspepsia, but notes that it shouldn't be used in the long term, and shouldn't be consistently used for any longer than 2 weeks due to the toxicity of ascaridole, one of its main components.