What Is Oregon Grape?

Oregon grape (Mahonia aquifolium or Berberis aquifolium) is a medicinal herb from the plant family of Berberidaceae. Long before the Europeans and other immigrants began to arrive in America, indigenous tribes used Oregon grape for many ailments including fever, arthritis, jaundice, diarrhea, and other maladies.

The herb was also used in native cultures to stimulate appetite. Today, Oregon grape is commonly used as a substitute for goldenseal (which is now considered an endangered species due to over-harvesting), offering similar antimicrobial properties.

The Oregon grape is a bushy perennial plant with shiny leaves that resemble holly. When it is fully grown, the shrub is between 2 to 6 feet high. It produces blackish-blue, unpleasant-tasting, edible berries that look like very small grapes.

Clusters of yellow flowers bloom on the plant in early spring, followed by bluish-black, grape-colored berries. After a few years of its life cycle, the leaves of the plant turn bright red. The golden yellow roots of the plant are used for its medicinal properties.

Also Known As

Other names used for Oregon grape include holly-leaf barberry, mountain grape, Oregon grape holly, Oregon barberry, blue barberry, creeping barberry, holly barberry, holly-leaved Berberis, holly Mahonia, Mahonia, Mahonia aquifolium, Mahonie, scraperoot, trailing Mahonia, Uva de Oregon, Vigne de l'Oregon and water-holly.

The name Oregon grape is somewhat misleading because the fruit it bears is not actually a grape, and while the plant does grow in the mountainous regions of the Pacific Northwest region of the United States—including Oregon— it is known to flourish in many other areas of the country, as well.

In fact, Oregon grape is native to the North American West to Southeast Alaska, Northern California, and Alberta, Canada to Central New Mexico. It is often seen in Douglas fir forests and in brushlands of the Rocky Mountains, the Cascades, and the Northern Sierras.

Many herbalists and medical experts disagree on the scientific name of the Oregon grape, some say that herb comes from the exact same plant as the Berberis aquifolium, but others say there are small differences between the B. aquifolium and M. aquifolium.

Possible Side Effects of Oregon Grape

Verywell / Nusha Ashjaee

What Is Oregon Grape Used For?

The root of Oregon grape has been used as herbal medicine to treat many maladies including colds, flu, herpes, hepatitis, syphilis, stomach upset, cancer, skin disorders, yeast infections, and more. Herbalists have touted the use of Oregon grape, claiming that it is effective in stimulating liver function, treating infections, and supporting digestive health. 

It’s important to note that there are limited clinical research study results available on the safety and health benefits of Oregon grape.

In fact, most of the published clinical research study results on Oregon grape involved the use of the root of the herb in a topical (administered on the skin) cream, for the treatment of a skin condition called psoriasis.

Oregon grape has also been used for its digestive stimulant properties (relieving spasms in the intestinal tract), antimicrobial properties (including its anti-fungal, antibacterial, and anti-parasitic action), immune-boosting, and anti-inflammatory properties.

Medical Uses

Oregon grape has been demonstrated to help lower blood sugar in patients with insulin resistance. It also has some cholesterol-lowering effects.

The herb has traditionally been used for maladies including, eye infections, acne, athlete's foot, gastrointestinal issues, skin conditions, and more, though there is limited scientific research on these claims.

Some studies have shown that Oregon grape may be effective for the treatment of giardia (a type of infectious diarrhea), eczema (an inflammatory skin condition) and as an herbal treatment for urinary tract infections.

The primary medicinal component of Oregon grape, berberine, has been shown to have anti-bacterial properties that are helpful in the treatment of several infections including, throat, intestinal, and urinary tract infections.

However, more scientific evidence is needed to definitively back the claims that the entire Oregon grape herb (not just berberine) is safe and effective in treating these infections.

Extensive medical research data has shown that Oregon grape may be safe and effective for the treatment of psoriasis (a common skin condition that causes skin cells to form scales and itchy, sometimes painful red patches).

How It Works

Berberine, an alkaloid derivative of many herbs, including goldenseal, barberry, and other herbs in the Berberis L genus, is known to have antibacterial and antifungal properties.

Alkaloids are thought to help fight various types of infections and have been used for the relief of conditions such as infectious diarrhea, chronic candidiasis (long-term yeast infection), and more.

Oregon grape is also thought to slow down the overproduction of immature skin cells and reduce inflammation in a skin condition called psoriasis.

Research Studies

Studies have shown that the active ingredient, berberine, contained in Oregon grape has effectively been used to treat diarrhea caused by E. coli infections.

Berberine is thought to slow down the mobility of the intestinal tract in those with diarrhea; it also inhibits the growth of bacteria and enhances immune cell properties, helping to prevent infections (particularly throat, intestinal, and urinary tract infections).

Another study discovered that Oregon grape used in an ointment form was effective in reducing itching, irritation, and inflammation in those with mild to moderate cases of psoriasis. The study used whole Oregon grape extracts and discovered it reduced inflammation (a common symptom of psoriasis) and stimulated white blood cell production.

In a 2006 double-blind study (the gold standard of clinical research studies) 200 participants were broken into two groups. One group was given the cream containing 10% Oregon grape extract, the other group was given a placebo two times each day for three months.

The study results indicated that those given the cream with Oregon grape received more benefits for skin conditions than those who used the placebo.  

Possible Side Effects

There are several side effects that have been reported from the use of Oregon grape, including:

  • Itching, burning, and irritation (at the site of topical cream administration)
  • Rash (particularly with topical use)
  • Diarrhea
  • Nausea and vomiting
  • Jaundice (yellowing of skin and eyes)
  • Kidney inflammation and irritation
  • Allergic reactions
  • Liver toxicity

Potential Drug Interactions

Certain medicines may interact with Oregon grape and may interfere with the body’s ability to break down some types of medications in the liver. Anyone taking prescription medication should consult with the healthcare provider before taking Oregon grape.

Examples of medications that should not be taken with Oregon grape include:

  • Cyclosporine (Neoral, Sandimmune)
  • Tetracycline
  • Doxycycline
  • Any medications that are changed by the liver

Some medications that are broken down in the liver may be broken down differently (causing increased side effects of some medications).

Always consult with your healthcare provider before using Oregon grape to ensure its safe use, in particular, when taking any type of medication. This includes other herbal supplements and over the counter medications and nutritional/medicinal supplements.

Safety Precautions

Oregon grape is not recommended for people who are pregnant (it is thought to cross the placental barrier and may harm the fetus). Oregon grape is not safe for use by people who are breastfeeding; brain damage has been reported in newborn infants exposed to berberine, which can be transferred to the infant via breast milk.

The safety of Oregon grape has not been established for use in children (particularly in newborns).

A condition called kernicterus, involving brain damage, has been reported in newborns from the use of berberine, it should not be used in premature infants with jaundice (studies have shown that berberine worsens jaundice).

Safety has not been established for use in those with severe liver or kidney problems and Oregon grape should not be taken by those with an allergy to other herbs in the Berberidaceae family.

It is recommended that Oregon grape (taken by mouth) is used no longer than two to three weeks before taking a break from its use. Long-term internal use is not recommended; long-term use has been found to lead to adverse reactions such as damage to the natural probiotics in the gastrointestinal system and liver toxicity.

Some medical experts report that there is not enough medical research evidence to prove that Oregon grape is safe when ingested. 

Oregon grape tea supplement

Verywell / Anastasia Tretiak

Dosage and Preparation

Oregon grape has been commonly used as a tea by boiling several teaspoons (5 to 15 grams) of chopped roots in 2 cups (500 ml) of water for 15 minutes, then cooling and straining the mixture.

Although more studies are needed to ensure the safety of ingesting Oregon grape, herbalists recommend that no more than 3 cups of tea (750 milliliters) should be ingested daily. 

Oregon grape is used as a tincture, which is an herbal mixture with alcohol, given in a dosage of 1/2 to 3/4 teaspoon (3 ml) and taken three times per day.

As a topical (on the skin) cream for psoriasis, a specific mixture of 10% Oregon grape bark extract cream is commercially made by a company named Relieva, Apollo Pharmaceutical to be applied two to three times per day to the affected area (for eight weeks) of the skin. Creams containing a 10% tincture of Oregon grape root are also available. 

What to Look For

Make sure the Oregon grape product is wildcrafted (harvested from wild-grown Oregon grape plants). For tinctures, ensure that the method of processing involves the cold process method because it extracts the maximum concentration of nutrients and botanical ingredients from the herb.

A Word From Verywell

Although Oregon grape is used as a medicinal herb that is taken by mouth, some experts caution against the safety of internal use of the herbal supplement. This is because there is not enough evidence from clinical research studies on the safety and effectiveness of the use of oral (by mouth) Oregon grape root.

Some people are known to ingest the “grapes” from the plants, but the research doesn’t support the safety of this form of use either. As with all other herbal supplements, always consult with a trusted healthcare provider before the use of Oregon grape in any form, but particularly before ingesting it.

Frequently Asked Questions

  • What are the main benefits of Oregon grape root?

    Oregon grape root has been used as an herbal medicine to treat conditions like the cold, flu, herpes, hepatitis, syphilis, upset stomach, and more. However, there is limited scientific evidence for its safety and health benefits. Speak to a doctor first before trying it for any condition.

  • How is Oregon grape used?

    Depending on the health benefits you are looking for, Oregon grape can be ingested, applied topically as a cream, or used in a tincture. A tincture is a solution made by dissolving or infusing an herb in alcohol.

  • Can Oregon grape be used for psoriasis?

    Yes, Oregon grape is available over the counter as a cream for topical use. It can be used to treat psoriasis, an autoimmune disease that causes skin to become scaly and irritated. If you think you have psoriasis, contact a doctor before self-treating with Oregon grape or other remedies.

  • Is berberine the same as Oregon grape?

    No. Berberine is a chemical that is extracted from Oregon grape. It is also found in goldenseal (Hydrastis canadensis) and barberry (Berberis vulgaris). Berberine is the ingredient in Oregon grape thought to give the herb its antibacterial and antifungal properties.

  • Is the fruit of the Oregon grape plant edible?

    Yes. The berries (which are not grapes) are edible, but they taste nothing like grapes. In fact, they are very tart, but they are rich in vitamin C. Keep in mind that there is limited scientific evidence on the safety of Oregon grape when ingested. Unlike the Oregon Grape root, the berries do not offer any medicinal properties.

  • Would Oregon grape be considered a good option for treating diabetes?

    No. Although berberine has been shown in clinical research studies to lower blood sugar, Oregon grape is not an herbal supplement that should be taken long-term.

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2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Yin J, Xing H, Ye J. Efficacy of berberine in patients with type 2 diabetes mellitusMetabolism. 2008;57(5):712‐717. doi:10.1016/j.metabol.2008.01.013

  2. Kong W, Wei J, Abidi P, et al. Berberine is a novel cholesterol-lowering drug working through a unique mechanism distinct from statinsNat Med. 2004;10(12):1344‐1351. doi:10.1038/nm1135

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