White oak bark comes from the *Quercus alba* tree. High tannin levels give it strong astringent properties. Herbalists traditionally use it to help with occasional diarrhea. A diluted rinse can soothe minor mouth or throat irritation.
People take it as a tea, tincture, or liquid extract. Tannins can reduce iron absorption, so separate white oak from iron supplements and iron-rich meals. Tannin-heavy extracts might have mild blood-thinning effects. Exercise caution if you take anticoagulant or antiplatelet medications.
Pregnant or breastfeeding individuals should avoid white oak. Safety data in these groups is missing. Discuss any herbal supplement with a healthcare professional before taking it.