The Health Benefits of Oak Bark

Claims about cough, diarrhea, wounds, and many other uses

Oak bark chips, shavings, and tincture

Verywell / Anastasia Tretiak

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Oak bark (Quercus robur), or white oak, comes from a tree in the Fagaceae family. Only the bark of the tree is used as an herbal remedy. It is believed to have many health-promoting properties that have the potential to help various skin conditions, digestive disorders, and other health concerns.

Oak bark is available in many forms, including tea, powder, pills, and liquid extracts. It can be ingested or used topically (applied to the skin).

This article looks at the medicinal uses of oak bark, how it may work, possible side effects, and how to use it.

Also Known As

Other names for oak bark include:

  • Common oak
  • Corteza de roble
  • Durmast oak
  • English oak
  • Pedunculate oak
  • Sessile oak
  • Stave oak
  • Stone oak
  • Tanner's bark, Tanner's oak

Health Benefits

Preliminary research now supports many of the traditional uses of oak bark. Many of oak bark's health benefits appear due to the tannins it contains. Up to 20% of oak bark is made up of these specific antioxidants.

Tannins are a yellowish or brownish, bitter-tasting organic substance. They're found in the bark and galls (abnormal growths) of many plants. Tannins are classified as polyphenols, a type of antioxidant.

Oak bark also contains other polyphenols and substances called saponins that are believed to have medicinal uses.

While research in the lab and on animals has been promising, human trials are in their earliest stages. Researchers don't know for sure about the risks and benefits of oak bark for any particular condition.

Oak bark and other herbal remedies shouldn't be used in place of conventional treatments. They're best used with your doctor's approval and alongside standard treatment.

Read on for a review of the research on the purported uses of oak bark.

Digestive Problems

Some early lab research suggests the tannins and other polyphenols in oak bark can protect the stomach from toxins.

Oak bark also appears to prevent inflammation in the digestive tract. It's sometimes used for:

Some research has demonstrated beneficial effects on gut bacteria and inflammation.

Respiratory Illness and Other Infections

Saponins have long been used in traditional Chinese medicine. Research suggests they have antioxidant, antiviral, antibacterial, anticancer, and anti-inflammatory effects. They may also work as an expectorant, making coughs more productive.

Oak bark also contains the antioxidant octyl gallate. It, along with tannins, may inhibit numerous viruses, including:

Octyl gallate may work, in part, by keeping viruses from clinging to cells in your body.

These qualities may make oak bark effective for treating:

The tannins in oak bark may also be toxic to fungi and yeast.

Allergies

Oak-bark tannins may also help treat allergies.

In one lab study, oak bark blocked allergic reactions at the cellular level. It prevented cells from releasing several secretions that drive the allergic response.

Pain, Inflammation, and Recovery

Oak bark may have some use as a painkiller and anti-inflammatory. It may also have value for recovery from surgery and athletic training.

Research on hysterectomy recovery suggests that an oak-bark product called Robuvit:

  • Reduced oxidative stress, which tends to increase after surgery
  • Lessened the need for other pain medications
  • Improved measures of general health, social functioning, and mental health
  • Was well tolerated by all study participants

Two small studies on Robuvit use for recovery in athletes suggest that the supplement improved performance and sped up recovery. Researchers said it:

  • Improved running and triathlon completion times
  • Decreased muscle pain, cramps, and inflammation
  • Lowered training-related oxidative stress
  • Reduced training-related hemolysis (destruction of red blood cells)
  • Improved recovery times, which allowed for more training

Heart and Liver Health

Oak bark may be beneficial to the health of your heart and liver.

In one animal study, a type of tannin from oak bark called ellagitannin:

  • Reversed the negative effects of a high-carbohydrate and high-fat diet
  • Improved the structure and function of the liver
  • Improved the structure and function of the heart
  • Lowered systolic blood pressure

Saponins are thought to help lower cholesterol by breaking down fat in the digestive tract. However, the specific saponins in oak bark have yet to be tested for this function.

Cancer

Oak bark has shown promise for the treatment and prevention of some types of cancer, according to a growing body of research.

Several lab and animal studies have identified substances in oak bark that may help delay or prevent cancer or cancer recurrence. These include:

  • Tannins
  • Triterpenoids, which are a type of saponin
  • Polyphenols

In lab-based studies, oak bark has been shown to have an effect against several types of cancer, including:

Some animal studies have shown that compounds in oak bark may stop cancer cells from spreading.

Skin Issues

Animal and human studies have shown oak bark extract to have antiseptic, anti-inflammatory, and wound-healing properties when applied to the skin.

Some of these properties may be due to oak bark being an astringent, which means it contracts skin cells, blood vessels, and other tissues. That can help stop bleeding and promote healing.

In addition, tannins have antiseptic properties thought to speed up blood clotting. Saponins may protect the skin against damage from the sun, kill the bacteria that cause acne, and strengthen capillaries (small blood vessels) in the skin.

Due to these effects, topical uses of oak bark include:

  • Mouth sores and bleeding gums
  • Skin irritation
  • Inflamed skin
  • Hemorrhoids
  • Bleeding cuts or wounds

Recap

Certain substances in oak bark give it suspected medicinal properties. It may be especially useful for diarrhea, skin irritation, and wound healing. However, so far, medical research hasn't confidently established whether oak bark is effective for any use.

Possible Side Effects

In most studies, oak bark has been reported as well tolerated. However, some people may be allergic to it.

Some research suggests that the tannins in oak bark can have some serious side effects. These include:

  • Poor digestion and impaired absorption of nutrients, including iron
  • Liver and kidney damage
  • Throat and esophageal cancer

These possible side effects appear to contradict some of the purported uses of oak bark. Conflicting information like this is one reason more research needs to be done before conclusions are drawn about oak bark's safety and effectiveness.

Contraindications

A contraindication is a circumstance that makes a treatment unsafe. Contraindications for oak bark may include:

  • Pregnancy or breastfeeding
  • Age 11 and younger
  • Cardiac (heart) conditions
  • Skin conditions or burns with large areas of broken or damaged skin
  • Eczema
  • Hypertonia (a nerve condition that causes muscles to tighten)
  • Kidney or liver conditions
  • Gastrointestinal (stomach and intestine) problems

Selection, Preparation, and Storage

Oak bark shavings

Verywell / Anastasia Tretiak

Oak bark can be made into a tea to drink for systemic symptoms like diarrhea and cough. For topical uses, you can apply an oak-bark compress to your skin or add it to bathwater.

An oak bark tincture can be made by mixing oak bark with alcohol. Tinctures are typically held under the tongue for a few seconds and then swallowed.

Dosing

There are currently no hard facts about exactly what constitutes a safe and effective dose of oak bark. Be sure to consult with a healthcare provider or other medical professional before taking it.

In general, dosages of herbal supplements depend on many factors including your age, general health, what it's being used for, and more.

Always follow your doctor's directions or the package instructions, and don't take more than recommended.

Common dosages for oak bark include:

  • Supplement: A coated tablet with 140 milligrams (mg) of dry extract can be taken by mouth by adults and kids over age 12 four times per day for unspecified acute diarrhea.
  • Bath, compress, or tea: One to two tablespoons of oak bark boiled for 20 minutes in two cups of water. Apply to the skin or drink three to five times per day.

According to Europa (European Medicines Agency), a dry extract can be made to treat acute diarrhea using a ratio of 5.0-6.5:1 extraction solvent: ethanol 50% V/V.

Absorption of oak bark in the intestinal tract is sometimes delayed. That means oak bark should be taken by mouth an hour or more before or after any medications or other herbal supplements.

Store oak bark preparations in a cool, dry place, out of direct sunlight.

What to Look For

The dried bark of young branches should be used for medicinal preparations of oak bark. Check the label for Quercus robur or one of oak bark's other names.

Hundreds of tree species are called oaks. But the genus Quercus (the Latin word for oak tree) includes deciduous trees or live oaks that are native to the northern hemisphere.

The following are not the same as oak bar, but they are in the same family. Bark from these related trees is sometimes sold for the same uses:

  • Quercus alba
  • Quercus cortex
  • Quercus pedunculata
  • Quercus petraea
  • Quercus sessiliflora

Recap

As with the health benefits of oak bark, its safety is also not confirmed. Make sure you consult your doctor for advice on using oak bark, as it is not for everyone. If you take it, follow dosing instructions you are given or that are on product packaging.

Frequently Asked Questions

Is white oak poisonous?

Parts of it are. The leaves and the acorns of the white oak tree have been known to be poisonous to animals (such as cattle and sheep) when ingested in large amounts. 

This is due to high levels of tannins, which could irritate the gastrointestinal system and cause damage to the organs, including the kidneys and liver.

However, oak bark doesn't appear to be toxic when consumed as part of the regular diet or when taken in medicinal dosages for limited periods of time. More research is needed to confirm this.

Do the tannins in oak bark have any side effects?

Yes, when large amounts are ingested, tannins can cause:

  • Stomach irritation
  • Nausea
  • Vomiting
  • Liver damage
  • Irritation of the skin and mucous membranes

Long-term high intake may be associated with:

  • Constipation
  • Poor digestion
  • Impaired iron absorption

It's suspected that regular high doses of tannins may increase the risk of certain cancers, including throat and esophageal cancer, but more research is needed in this area.

Summary

Saponins and polyphenols, especially tannins, are thought to give white oak bark several medicinal benefits. Some evidence suggests it has antioxidant, antiviral, antibacterial, anti-cancer, and anti-inflammatory properties, among others.

While there's growing evidence supporting oak bark as a treatment for many conditions—including digestive disorders, pain, inflammation, cancer, wounds, and skin problems—none of these uses are conclusively proven. The safety profile isn't well established, either.

You can use oak bark as a supplement, tea, tincture, or topical treatment, depending on the use. Side effects are possible and oak bark likely isn't safe for everyone. As with any supplement, talk to your doctor before starting it.

A Word From Verywell

Natural treatments can seem safer than pharmaceutical drugs. However, many can cause serious side effects. Herbal medicine may very well have a useful place in the treatment of some conditions, but it's important to use it with cautious.

Talk to your doctor before adding anything to your treatment regimen. It's also good to check with your pharmacist about whether an herbal treatment like oak bark could interact negatively with any of your medications.

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