Nature's Sunshine White Oak Bark is rich in tannin. Tannins give white oak bark its bitter and astringent qualities and may have an astringent effect on tissues. This herb is commonly used for supporting skin health.
The White Oak (Quercus alba) is a species of oak in the white oak group Quercus sect. Quercus. It is native to eastern North America, from southern Quebec west to eastern Minnesota, and south to northern Florida and eastern Texas.
Normally not a very tall tree, typically 20-25 m tall at maturity, it nonetheless becomes quite massive and its lower branches are apt to reach far out laterally parallel to the ground. The tallest known white oak is 44 m tall. It is not unusual for a white oak tree to be as wide as it is tall. Conversely, specimens at high altitude may only be small shrubs. White oaks have been known to live over five hundred years. The bark is a light ash-grey and somewhat peeling, variously from the top, bottom and/or sides.
White oak was an important part of native American herbal medicine used for diarrhoea, haemorrhoids and to treat wounds. White oak listed in the US Pharmacopoeia (1820-1916) as an antiseptic, astringent and tonic.
It is rich in tannins (quercitannic acids) known for their ability to shrink blood tissues and constrict and strengthen blood vessels. White oak bark tannins also exhibit antimicrobial and antiviral activity. White oak bark also acts as a mild diuretic to flush toxins and irritants from the body.
White oak tannins have also been shown to inhibit the proliferation of intestinal parasites and treat ringworm.