Oak Bark
What is it? Overview Usage Side Effects and Warnings

What is Oak Bark?

The oak tree, respected for millennia as a source of strong, dense wood, also has a considerable tradition of medicinal use. The astringent, tannin-rich bark of the oak tree has been recommended for such diverse conditions as internal hemorrhage, diarrhea, dysentery, cancer, and pneumonia.

Currently, Germany’s Commission E recommends oak bark internally for treatment of diarrhea and topically for sore throat , mouth sores , hemorrhoids , and eczema . However, there is no meaningful scientific evidence that oak bark offers any therapeutic benefit in these or any other conditions. Only double-blind , placebo-controlled studies can prove a treatment effective, and none have been performed on oak bark. (For more information on why such studies are essential, see Why Does This Database Rely on Double-blind Studies?) Oak bark contains numerous substances in the tannin family, especially ellagitannin, 1 along with potentially active substances in the saponin family. 2 Tannins are thought to have an astringent effect, meaning that they reduce tissue swelling and stop...

Safety Issues

Although comprehensive safety testing has not been performed, use of oak bark is not generally associated with any side effects other than the occasional digestive upset or allergic reaction. Safety in young children, pregnant or nursing women, or people with severe liver or kidney disease has not been established.