What Is It?
From generation to generation, the majestic oak tree has provided shade on sunny days, timber for furniture-makers and ship-builders, and even food in times of famine. Many Native American tribes relied on its acorns for nourishment.
Not surprisingly, medicinal uses for the oak tree have a long history as well. Of the hundreds of Quercus species found in the northern hemisphere, Quercus alba is most valued in North America for medicinal purposes. Europeans rely more heavily on Quercus robur and Q. petraea.
The most important healing component in the smooth bark of the oak tree is its tannin, which has astringent and mildly antiseptic qualities. The tannin is what makes oak bark so valuable for minor wounds and inflammation, for tightening tissue and lessening oozing.
The astringent qualities of oak bark account for why German health authorities consider topical formulations such as lotions effective for treating inflammatory skin conditions. Irritating and itchy patches of eczema, bleeding or infected skin sores, inflamed hemorrhoids, and even shingles lesions tend to respond well to oak bark. Bathing in specially formulated oak bark preparations sometimes provides relief as well.
Oak bark’s powerful anti-inflammatory qualities make it very useful (in strong tea form) for sore throat and inflamed gums. Slightly weaker teas, capsules, and liquid extracts are worth trying for acute diarrhea, but only for a case that’s clearly not caused by an underlying condition. The herb’s astringent tannins lessen intestinal inflammation and related diarrhea.
Interestingly, a commercial oak bark preparation (Litiax), which is only available in Europe, is used for kidney stones. The product acts as a diuretic (water pill), it reduces pain and inflammation, and is believed to prevent the formation of new stones.
Researchers are also exploring the value of oak bark for treating vaginal infections. And recent experiments with animals suggest oak bark may also have promise as a cholesterol-lowering agent.
Oak bark is commonly available as a dried bark, liquid extract, and tincture. When preparing a topical formulation for skin inflammation or other irritation, soak a cloth in a strongly prepared tea and apply the compress to the affected area three times a day. Commercial bath formulations containing oak bark are also available; follow the package instructions.
A tea for diarrhea or other internal problems can be prepared by simmering approximately 1 teaspoon of the finely chopped bark in 1 cup (8 ounces) of water for a few minutes, then straining. Drink three cups a day. If you don’t like the taste and would prefer a liquid extract, mix 1 teaspoon of the extract in 1/4 cup (2 ounces) of water. Drink this mixture three times a day.
If you’re on other medications, talk to your doctor before taking oak bark preparations internally; the bark could reduce or inhibit the absorption of the other medicines. You might need to take more (or less) of the medicine to get the same effect.
Oak bark preparations have been safely used for decades. However, it’s important not to take an oak bark bath or place large amounts of the preparation on skin that’s severely burned or wounded, or on weeping eczema because this could further irritate the area.
Oak bark contains a relatively large concentration of tannin (8 to 10%). Any plant that has more than 10% tannin can cause gastrointestinal disturbances in sensitive individuals. Used over a long period of time, and at high doses, plants containing tannin can cause kidney damage, although this problem has not been found with oak bark.
David Edelberg, MD