- 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).
- 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.
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.
*Key to grades:
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.
Adults (18 years and older):
- There is no proven safe or effective dose for white oak. Traditionally, oak bark has been ground to a fine powder and inhaled freely to treat tuberculosis. For diarrhea or dysentery, a decoction of 1 ounce of bark in a quart of water, boiled down to a pint and taken in “wineglassful” doses has been used for no longer than 3-4 days. For chronic sore throat, a decoction of 1 ounce of bark in a quart of water boiled down to a pint and gargled has been used.
- White oak has also been applied on the skin. Traditionally, a preparation has been formulated by mixing 2 teaspoons of coarsely powdered bark in 500 milliliters of water, followed by straining the solution. Oak bark is not recommended for topical use longer than 2-3 weeks. A decoction of 1 ounce of bark in a quart of water, boiled down to a pint has been applied topically for bleeding gums or piles.
Children (younger than 18 years):
- There is no proven safe or effective dose for white oak, and use in children is not recommended.
The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
- Avoid white oak in individuals with a known allergy or hypersensitivity to white oak. Caution is advised in those with allergies to peanuts or tree pollens. One patient experienced an anaphylactic reaction after eating acorn nuts, fruit of the holm oak (a related species, Quercus ilex), who was also allergic to peanuts.
Side Effects and Warnings
- White oak is generally regarded as safe (GRAS) in the United States, and is often used on an as needed basis, orally and topically. However, there is very little scientific information available supporting the safety of white oak.
- Gastric irritation, nausea, and vomiting have occurred in association with the ingestion of large doses of white oak.
- Although not well studied, white oak may cause hepatic (liver) dysfunction; plants with at least 10% tannins may cause necrotic (dead tissue) conditions of the liver. Tannins found in white oak may have adverse effects on the kidneys. Use cautiously in patients with renal (kidney) or hepatic (liver) dysfunction. Avoid oak bark baths in those who have cardiac insufficiency (stages III and IV (NYHA)), eczema, hypertonia (muscle tension) or infection.
Pregnancy and Breastfeeding
- White oak is not recommended in pregnant or breastfeeding women due to a lack of available scientific evidence.
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Interactions with Drugs
- Combining white oak with medications that may damage the liver (hepatotoxic) should be avoided due to possible additive side effects. Caution is advised.
- Tannins found in white oak may theoretically have adverse effects on the kidneys; plants with at least 10% tannins may cause kidney damage. Consult with a qualified healthcare professional, including a pharmacist, before combining therapies.
Interactions with Herbs and Dietary Supplements
- Combining white oak with herbs and supplements that may damage the liver (hepatotoxic) should be avoided due to possible additive side effects. Caution is advised.
- The primary chemical constituents of oak bark include tannins (phlobatannin, ellagitannins, gallic acid), gallotannins and quercetin. Patients taking quercetin should use caution as there may be additive effects. Tannins found in white oak may theoretically have adverse effects on the kidneys; plants with at least 10% tannins can cause kidney damage. Herbs or supplements with a high tannin percentage may also cause precipitation of constituents of other herbs. Consult with a qualified healthcare professional, including a pharmacist, before combining therapies.
- White oak also contains the minerals manganese, calcium, iron, and zinc. Large doses may cause additive effects with multivitamins containing these vitamins and minerals.
Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.
- This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration ().
- Blumenthal M, et al, ed. The CompleteGerman Commission E Monographs: Therapeutic Guide to Herbal Medicine. Trans. S. Klein. Boston, MA: American Botanical Council, 1998
- Brinker F. Herb Contraindications and Drug Interactions. 2 ed. Sandy, OR: Eclectic Medical Publications, 1998.
- Garg SK, Makkar HP, Nagal KB, et al. Oak (Quercus incana) leaf poisoning in cattle. Vet.Hum.Toxicol. 1992;34(2):161-164.
- Kinde H. A fatal case of oak poisoning in a double-wattled cassowary (Casuarius casuarius). Avian Dis. 1988;32(4):849-851.
- Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2 ed. New York, NY: John Wiley & Sons, 1996.
- Lin RY, Clauss AE, Bennett ES. Hypersensitivity to common tree pollens in New York City patients. Allergy Asthma Proc 2002;23(4):253-258.
- Loria RC, Wilson P, Wedner HJ. Identification of potential allergens in white oak (Quercus alba) pollen by immunoblotting. J Allergy Clin Immunol 1989;84(1):9-18.
- Maciejewska A, Wojtczak J, Bielichowska-Cybula G, et al. [Biological effect of wood dust]. Med Pr 1993;44(3):277-288.
- Mammela P, Tuomainen A, Vartiainen T, et al. Biological monitoring of wood dust exposure in nasal lavage by high-performance liquid chromatography. J Environ.Monit. 2002;4(2):187-189.
- McCune LM, Johns T. Antioxidant activity in medicinal plants associated with the symptoms of diabetes mellitus used by the indigenous peoples of the North American boreal forest. J Ethnopharmacol. 2002;82(2-3):197-205.
- McGuffin M, et al., ed. American Herbal Products Association’s Botanical Safety Handbook. Boca Raton, FL: CRC Press, 1997.
- Schultz V, Hansel R, Tyler VE. Rational Phytotherapy: A Physician’s Guide to Herbal Medicine. Terry C. Tegler, transl. 3 ed. Berlin, Germany: Springer, 1998.
- Vega A, Dominguez C, Cosmes P, et al. Anaphylactic reaction to ingestion of Quercus ilex acorn nut. Clin Exp Allergy 1998;28(6):739-742.
- Weiss RF. Herbal Medicine. Beaconsfield, UK: Beaconsfield Publishers Ltd., 1988, 328-29.
- Wichtl MW. Herbal Drugs and Phytopharmaceuticals. Ed. N.M. Bissett. Stuttgart Medpharm GmbH Scientific Publishers, 1994.
Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to . Selected references are listed below.