Oak bark's therapeutic uses
Oak bark, derived from the Quercus genus of trees, has been traditionally utilized for various therapeutic purposes due to its rich content of tannins and other active compounds. It is primarily proposed for treating diarrhea, with historical use also attributed to conditions such as canker sores, eczema, hemorrhoids, sore throat, and skin ailments. The astringent properties of oak bark are believed to reduce tissue swelling and bleeding, making it a candidate for internal and topical applications. While indigenous cultures have long valued oak bark for its potential anti-inflammatory, antibacterial, and antioxidant effects, scientific studies validating these claims remain sparse. Recommendations from Germany's Commission E support its use for diarrhea and skin issues, yet there is a lack of robust clinical evidence confirming these benefits. Additionally, some preliminary studies suggest that oak bark may have antimicrobial properties and might aid in gum health, but further research is necessary to substantiate these assertions. Generally, oak bark is considered safe, with rare instances of digestive upset or allergic reactions reported, although its safety in children and pregnant women is not established.
Subject Terms
Oak bark's therapeutic uses
DEFINITION: Natural plant product used to treat specific health conditions.
PRINCIPAL PROPOSED USE: Diarrhea
OTHER PROPOSED USES: Canker sores, eczema, hemorrhoids, sore throat, oral health, skin conditions, wound healing, diarrhea treatment, varicose veins, excessive sweating
Overview
The oak tree, prized for millennia because of its strong, dense wood, also has a considerable tradition of medicinal use. Its astringent, tannin-rich bark has been recommended for such diverse conditions as internal hemorrhage, diarrhea, dysentery, cancer, and pneumonia.
Therapeutic Dosages
A typical oral dose of oak bark is 1 gram three times daily. For application as a treatment for eczema, an oak bark tea is made by boiling 1 to 2 tablespoons of the bark for twenty minutes in 2 cups of water, and this is applied to the rash three to five times daily. Oak tinctures and extracts should be used according to label instructions.
Therapeutic Uses
A 2020 article in the medical journal Evidence-Based Complementary and Alternative Medicine noted that for millennia, Indigenous people throughout the globe have employed the 600 species of plants of the Quercus genus for therapeutic purposes. This has been done for purported benefits from their anti-inflammatory, antibacterial, and antioxidant properties and other positive effects. While acknowledging the length of time employed and the myriads of ailments these plants are ascribed to alleviate, the journal did acknowledge that further investigation was required to fully determine their functionality and potential toxicity.
Germany’s Commission E recommends internal use of oak bark to treat diarrhea and topically for sore throat, mouth sores, hemorrhoids, and eczema. However, no meaningful scientific evidence exists that oak bark offers therapeutic benefits in these or other conditions. Only double-blind, placebo-controlled studies can prove a treatment effective, and none have been performed on oak bark.
Oak bark contains numerous substances in the tannin family, especially ellagitannin, along with potentially active substances in the saponin family. Tannins are thought to have an astringent effect, meaning that they reduce tissue swelling and stop bleeding, and they are traditionally thought to be useful for diarrhea. However, oak bark has never been studied as a treatment for diarrhea. Saponins are often said to act as expectorants, enhancing the ability to cough up phlegm. Again, however, there is no direct evidence that oak bark is useful for coughs or related conditions.
Evidence that is too weak to be relied upon hints that oak bark may have value for kidney stones, possibly reducing pain and slowing stone growth. In addition, test-tube studies indicate that oak bark solutions applied topically might have activity against various microorganisms, including Staphylococcus bacteria, and might also exert cancer-preventive effects. However, it is a long way from such studies to actual evidence of clinical benefit.
Several other therapeutic uses for oak bark exist, although these claims require further scientific study. Oak bark’s efficacy in treating eczema may make it beneficial for other skin conditions, such as wound healing. It may reduce inflammation and itch from insect bites and stings and help prevent infection in cuts, scrapes, and burns. Oak bark may also be beneficial for gum health and preventing gingivitis. Its anti-inflammatory properties may reduce swelling and increase circulation in individuals with varicose veins. Some research suggests that using oak bark in the bath may help prevent excessive sweating.
Safety Issues
Although comprehensive safety testing has not been performed, the 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, and people with severe liver or kidney disease has not been established.
Bibliography
Cerda, B., F. A. Tomas-Barberan, and J. C. Espin. "Metabolism of Antioxidant and Chemopreventive Ellagitannins from Strawberries, Raspberries, Walnuts, and Oak-Aged Wine in Humans: Identification of Biomarkers and Individual Variability." Journal of Agricultural and Food Chemistry, vol. 53, 2005, pp. 227-235.
Gulluce, M., et al. "Antimicrobial Effects of Quercus ilex L. Extract." Phytotherapy Research, vol. 18, 2004, pp. 208-211.
Hatanaka, Miho. "Oak Bark: Benefits, Dosage, Side Effects, and More." Healthline, 4 June 2020, www.healthline.com/nutrition/oak-bark. Accessed 18 Sept. 2024.
"Oak – Health Information Library." PeaceHealth, 24 May 2015, www.peacehealth.org/medical-topics/id/hn-2137005. Accessed 18 Sept. 2024.
Taib, Medhi, et al. "Medicinal Uses, Phytochemistry, and Pharmacological Activities of Quercus Species." Evidence-Based Complementary and Alternative Medicine, 31 July 2020, www.ncbi.nlm.nih.gov/pmc/articles/PMC7415107/#. Accessed 6 Sept. 2023.
Voravuthikunchai, S., et al. "Effective Medicinal Plants Against Enterohaemorrhagic Escherichia coli O157:H7." Journal of Ethnopharmacology, vol. 94, 2004, pp. 49-54.
Voravuthikunchai, S. P., and L. Kitpipit. "Activity of Medicinal Plant Extracts Against Hospital Isolates of Methicillin-Resistant Staphylococcus aureus." Clinical Microbiology and Infections, vol. 11, 2005, pp. 510-512.