Of the many species of oak found all over the world, the white oak (Quercus alba) is found primarily in North America. Although there are many species of the Quercus genus, many are thought to have similar properties. The parts of this tree used medicinally are the inner bark and the galls (growths that are produced in reaction to fungi or insects).
Traditionally, Native Americans and European settlers have used white oak for its astringent and anti-inflammatory properties. White oak was listed in the United States Pharmacopoeia from 1820 to 1919, and also in the National Formulary from 1916 to 1936.
Due to a lack of available scientific evidence, it is difficult to determine the safety of white oak. Adverse effects associated with white oak include gastrointestinal irritation, nausea and vomiting, which are theoretically due to its tannin content.
Black oak (Quercus tinctoria), British oak, common oak (Quercus pedunculata), durmast oak (Quercus sessiliflora), English oak (Quercus robur), Fabaceae (family), gallotannins, green oak (Quercus virens), holm oak (Quercus ilex), live oak (Quercus virens), Quebec oak, quercetin, red oak (Quercus petraea, Quercus rubra), royal protector, sessile oak, tanner's bark, tannins (phlobatannin, ellagitannins, gallic acid), turkey oak (Quercus cerris).
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.