Parts Used & Where Grown
Oak trees grow throughout North America. Some species of oak grow around the world, including in China and the Middle East. The bark of the oak tree is used medicinally.
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This supplement has been used in connection with the following health conditions:
|Refer to label instructions||Oak is an astringent herb that can be used as a mouth rinse to soothe the pain of canker sores. The herb contains tannins that can bind up fluids and possibly relieve inflammation.|
Historically, herbs known as astringents have been used to soothe the pain of canker sores. These herbs usually contain tannins that can bind up fluids and possibly relieve inflammation. They are used as a mouth rinse and then are spit out. None of these herbs has been studied in modern times. Examples of astringent herbs include agrimony, cranesbill, tormentil, oak, periwinkle, and witch hazel. Witch hazel is approved by the German Commission E for local inflammations of the mouth, presumably a condition that includes canker sores.
|Refer to label instructions||Oak is a tannin-containing herb that may be helpful to decrease diarrhea during acute flare-ups and has been used for this purpose in traditional medicine.|
Tannin-containing herbs may be helpful to decrease diarrhea during acute flare-ups and have been used for this purpose in traditional medicine. A preliminary trial using isolated tannins in the course of usual drug therapy for Crohn’s disease found them to be more effective for reducing diarrhea than was no additional treatment.2 Tannin-containing herbs of potential benefit include agrimony (Agrimonia spp.), green tea, oak, witch hazel, and cranesbill. Use of such herbs should be discontinued before the diarrhea is completely resolved; otherwise the disease may be aggravated.
|Refer to label instructions||A tannin in oak has been shown to inhibit intestinal secretion, which may help resolve diarrhea. In Germany oak is recommended to treat mild, acute diarrhea in children.|
In laboratory experiments, a tannin in oak, known as ellagitannin, inhibited intestinal secretion,3 which may help resolve diarrhea. Oak is well regarded in Germany, where it is recommended (along with plenty of electrolyte-containing fluids) to treat mild, acute diarrhea in children.4
|Refer to label instructions||Topical preparations containing calendula, chickweed, or oak bark have been used traditionally to treat people with eczema.|
|Refer to label instructions||Astringent herbs such as oak have been traditionally used for heavy menstruation.|
Cinnamon has been used historically for the treatment of various menstrual disorders, including heavy menstruation.6 This is also the case with shepherd’s purse (Capsella bursa-pastoris). 7 Other herbs known as astringents (tannin-containing plants that tend to decrease discharges), such as cranesbill, periwinkle, witch hazel, and oak, were traditionally used for heavy menstruation. Human trials are lacking, so the usefulness of these herbs is unknown. Black horehound was sometimes used traditionally for heavy periods, though this approach has not been investigated by modern research.
How It Works
How It Works
Tannins are the primary constituents of oak bark.8 These tannins are potent astringents, akin to those found in witch hazel (Hamamelis virginiana). Tannins bind liquids, absorb toxins, and soothe inflamed tissues. The oak tannin, known as ellagitannin, inhibits intestinal secretion,9 which helps resolve diarrhea. The nonirritating, astringent nature of oak has led to its recommendation for treating mild, acute diarrhea in children (along with plenty of electrolyte-containing fluids) in Europe.10 Astringents such as oak may also help relieve the pain of sore throats and canker sores.
How to Use It
The German Commission E monograph suggests 3/4 teaspoon (3 grams) of the bark per day.11 For eczema, oak is applied topically by first boiling 1–2 tablespoons (15–30 grams) of the bark for fifteen minutes in 2 cups (500 ml) of water. After cooling, a cloth is dipped into the liquid and applied directly to the rash several times per day. The liquid prepared this way in the morning can be used throughout the day. Unused portions should then be discarded. Up to 5 cups (1250 ml) of this same solution can be taken each day in cases of diarrhea. Alternatively, a tincture of oak, approximately 1/2 teaspoon (2–3 ml) three times daily, can be used.
Interactions with Supplements, Foods, & Other Compounds
Interactions with Medicines
Certain medicines interact with this supplement.
|Some medicines may increase the need for this supplement.|
|Some medicines interact with this supplement, so they should not be taken together.|
|Some interactions between this supplement and certain medicines require more explanation. Click the link to see details.|
Note: The following list only includes the generic or class name of a medicine. To find a specific brand name, use the Medicines Index.
|Acetaminophen with Codeine|
Except for the occasional upset stomach or constipation reported after drinking the tea, oak bark is rarely associated with side effects. There are no known reasons to avoid oak during pregnancy or breast-feeding, though oak can cause constipation. It is safe for use in children and infants. The German Commission E monograph warns against people with open sores, wounds, high fever, or infection bathing in water with oak bark.12
1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Foods, Drugs, and Cosmetics, 2d ed. New York: John Wiley & Sons, 1996, 485–7.
2. Plein K, Burkard G, Hotz J. Treatment of chronic diarrhea in Crohn disease. A pilot study of the clinical effect of tannin albuminate and ethacridine lactate. Fortschr Med 1993;111:114–8 [in German].
3. Konig M, Scholz E, Hartmann R, et al. Ellagitannins and complex tannins from Quercus petraea bark. J Nat Prod 1994;57:1411–5.
4. Schilcher H. Phytotherapy in Paediatrics. Stuttgart, Germany: Medpharm Scientific Publishers, 1997, 49–50.
5. Weiss RF. Herbal Medicine. Gothenberg, Sweden: Ab Arcanum and Beaconsfield: Beaconsfield Publishers Ltd, 1988, 328–9.
6. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Foods,Drugs, and Cosmetics, 2d ed. New York: John Wiley & Sons, 1996, 168–70.
7. Ellingwood F. American Materia Medica, Therapeutics and Pharmacognosy. Sandy, OR: Eclectic Medical Publications, 1919, 1998, 354.
8. Weiss RF. Herbal Medicine. Beaconsfield, UK: Beaconsfield Publishers Ltd., 1988, 328–9.
9. Konig M, Scholz E, Hartmann R, et al. Ellagitannins and complex tannins from Quercus petraea bark. J Nat Prod 1994;57:1411–5.
10. Schilcher H. Phytotherapy in Paediatrics. Stuttgart, Germany: Medpharm Scientific Publishers, 1997, 49–50.
11. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative Medicine Communications, 1998, 175–6.
12. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative Medicine Communications, 1998, 175–6.
Last Review: 08-17-2011
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The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2013.
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