What Is Oregon Grape?

Oregon grape (Berberis aquifolium or Mahonia aquifolium) is a medicinal herb from the plant family of Berberidaceae. Long before the Europeans and other immigrants arrived in America, American Indian tribes in the Pacific Northwest used Oregon grape for many ailments, including stomach problems, hemorrhages, tuberculosis, and arthritis.

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 tiny 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 plant leaves turn bright red. The golden yellow roots of the plant are used for their medicinal properties.

The name Oregon grape is somewhat misleading because the fruit it bears is not a grape. 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.

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, the Rocky Mountains' brushlands, the Cascades, and the Northern Sierras.

Herbalists and medical experts disagree on the scientific name of the Oregon grape. Some say that the herb comes from the same plant as the Berberis aquifolium, but others say there are slight differences between the B. aquifolium and M. aquifolium.

This article discusses the uses of Oregon grape in traditional medicine and clinical data that does or does not support these uses. It also covers side effects, interactions, and special precautions of Oregon grape.

Possible Side Effects of Oregon Grape

Verywell / Nusha Ashjaee

Dietary supplements are not regulated in the United States, meaning the FDA does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement that has been tested by a trusted third party, such as USP, ConsumerLabs, or NSF. However, even if supplements are third-party tested, that doesn't mean that they are necessarily safe for all or effective in general. It is important to talk to your healthcare provider about any supplements you plan to take and to check in about any potential interactions with other supplements or medications.

Supplement Facts

  • Active Ingredient(s): Berberine, alkaloids
  • Alternate Name(s): Oregon hollygrape, tall Oregon grape, hollyleaved barberry, creeping barberry, barberry, berberis
  • Legal Status: Herbal supplement
  • Suggested Dose: There is currently no recommended dose for Oregon grape. Tablet or capsule 0.2 - 1 grams per day berberine (an ingredient in Oregon grape) for up to three months, as a topical cream, applied to the skin 2-3 times per day.
  • Safety Considerations: Pregnancy, breastfeeding, jaundice, newborn babies, children, allergy

Uses of Oregon Grape

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or doctor. No supplement is intended to treat, cure, or prevent disease.

The root of Oregon grape has been used in herbal medicine to treat different disorders. Most of the published clinical research results on Oregon grape involved utilizing the root of the herb in a topical (administered on the skin) cream to treat a skin condition called psoriasis. The studies have also focused on one constituent of Oregon grape, berberine.

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.


It is believed that the alkaloid berberine, contained in Oregon grape, is responsible for the medicinal effects when used to treat psoriasis. Further studies are needed to confirm Oregon grape's effectiveness in treating this condition.

Diabetes mellitus

Lab and animal studies suggested berberine (one chemical found in Oregon grape) improved insulin sensitivity and secretion, and other outcomes (like inflammation) in cell cultures or mice. However, there is not enough human data suggesting that berberine alone is effective in treating diabetes.

What Are the Side Effects of Oregon Grape?

Oregon grape is considered generally safe. It has no toxicity. However, several side effects have been reported from the use of Oregon grape. Along with these side effects, as with all herbal supplements, is the possibility of an allergic reaction.

Common Side Effects

The side effects identified in the Oregon grape and berberine are common side effects, including:

  • Diarrhea
  • Constipation
  • Gas
  • Stomach upset
  • Itching, burning, and irritation (at the site of topical cream administration)
  • Rash (particularly with topical use)

Severe Side Effects

There are not many documented severe side effects of Oregon grape. An allergy to Oregon grape's constituents could cause anaphylaxis, a severe, life-threatening allergic reaction.

Consuming too much Oregon grape may have severe effects. The constituent berberine may have severe effects if taken in high quantities. There exists the possibility of jaundice if berberine is taken in high doses. Because Oregon grape contains berberine, taking high doses of Oregon grape may have the same results.


Oregon grape is not recommended for people who are pregnant or people who are breastfeeding due to the risk of causing jaundice to a newborn child. A condition called kernicterus, a type of brain damage may result if a newborn child is exposed to berberine.

Safety has not been established for use in children. Use by children is not recommended.

Avoid Oregon grape if you have an allergy to other herbs in the Berberidaceae family.

The long-term internal use of Oregon grape has not been studied. Until there is clinical data on the safety of long-term use, it is not recommended to take Oregon grape internally for an extended period.

Dosage: How Much Oregon Grape Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.

Few clinical studies about the proper dosage of Oregon grape have been completed. There is not enough data to determine an effective, safe dose of Oregon grape.

There are still clinical studies on the oral consumption of berberine, not specifically Oregon grape.

Berberine is an active constituent in Oregon grape. A dose of 0.2 - 1.0 grams per day of berberine in either tablet or capsule forms has been used for up to three months.

What Happens If I Take Too Much Oregon Grape?

Due to a lack of clinical data, an effective, safe dose of Oregon grape has not been determined. There is no information on upper limits specific to Oregon grape.

There is research regarding excessive use of berberine, a component within the Oregon grape. These studies are in the early stages, only having been done in animals. The known effective dose is not known for humans.

It is safest to speak with your healthcare provider about a dose of Oregon grape that would be best for you and your individual needs.


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 their healthcare provider before taking Oregon grape.

Examples of medications that should not be taken with Oregon grape or its component berberine include:

  • Cyclosporine (Neoral, Sandimmune)
  • Medicines for diabetes like metformin
  • Versed (midazolam)
  • Medications processed by special liver enzymes (CYP2C9, CYP2D6, CYP3A4)
  • Sedative medications

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

Interactions with supplements may include:

  • Herbs or supplements that may impact blood pressure (licorice, magnesium, niacin, potassium)
  • Herbs or supplements that may lower blood sugar (aloe, bitter melon, cassia cinnamon, chromium)
  • Herbs or supplements that may change how blood clots (garlic, ginger, ginkgo)
  • Sedating herbs or supplements (melatonin, valerian)

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

It is essential to read a supplement's ingredient list and nutrition facts panel to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.

Oregon grape tea supplement

Verywell / Anastasia Tretiak

How to Store Oregon Grape

Guidance for storing Oregon Grape can be found on the package. Follow the instructions on the package for storing and disposing of Oregon grape.

The dried root of Oregon grape can be stored in food or pharmaceutical-grade polyethylene bags. These bags of dried Oregon grape roots can be stored for up to two years in a dry space away from sunlight and pests.

Storage of other forms of Oregon grape should be followed and directed on the item's packaging. Do not use the product beyond the recommended length of storage. If the product has been stored longer than suggested, discard the product as instructed on the packaging.

Similar Supplements

  • Goldenseal (Hydrastis canadensis)
  • Yellowroot (Xanthorhiza simplicissima)
  • Amur corktree (Phellodendron amurense)
  • Chinese goldthread (Coptis chinesis)
  • Prickly poppy (Argemone polyanthemos)

Berberine is an alkaloid found in Oregon grape. Other supplements also contain berberine (ex., goldenseal). Having similar constituents means they may have similar effects, either negative or positive.

Frequently Asked Questions

  • What have Oregon grape root and berberine been studied for?

    Oregon grape root has been used as an herbal medicine to treat conditions like psoriasis , and berberine has been studied in animals and lab studies for diabetes mellitus. However, there is limited human evidence for its safe effectiveness. Please speak to a healthcare provider first before trying it for any condition.

  • How is Oregon grape used?

    Oregon grape has been used topically and orally in capsule or tincture form. A tincture is a solution by dissolving or infusing an herb with ethyl alcohol.

  • 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 are thought to not offer medicinal properties.

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

    No. While a chemical in Oregon grape (berberine) has been shown in animal and lab studies to lower blood sugar, Oregon grape should not be considered as a treatment for diabetes in humans. Speak with your healthcare provider about your options.

Sources of Oregon Grape & What To Look For

Oregon grape is available as a topical product, tincture, and in capsules.


Supplements of Oregon grape are easily found in herbal stores and online. Do your best to ensure the product you purchase is of good quality. Many stores offer supplements, but that does not guarantee that they are all of the same quality.

Supplements of Oregon grape can be found in tincture and capsule types. The type you choose is up to you. But again, do your best to ensure it is of the best quality.


Oregon grape is a medicinal plant with a history of use in the traditional medicine practices of Native American tribes of the Pacific Northwest. It has been used for several human ailments and conditions, but few of these claims have been verified by clinical studies.

Researchers have studied the effects of Oregon grape's constituent, berberine, on some health conditions. More studies are needed to confirm the benefits of berberine for diabetes mellitus and psoriasis.

Oregon grape is considered non-toxic but clinical studies still have to be done to understand any long-term effects it may have, along with any dosing limits.

When taking Oregon grape, discuss dosing and safety considerations with a healthcare professional. Oregon grape may interact with several medications and other supplements. Share with your healthcare provider all medications and supplements you are taking to avoid any possible interactions with Oregon grape.

8 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. Daw Sonya. Oregon Grape. National Park Service. 2018.

  2. Janeczek M, Moy L, Lake EP, Swan J. Review of the Efficacy and Safety of Topical Mahonia aquifolium for the Treatment of Psoriasis and Atopic DermatitisJ Clin Aesthet Dermatol. 2018;11(12):42-47.

  3. Pang B, Zhao LH, Zhou Q, et al. Application of berberine on treating type 2 diabetes mellitusInt J Endocrinol. 2015;2015:905749. doi:10.1155/2015/905749

  4. National Library of Medicine. Berberine. Medline Plus. 2021.

  5. Health University of Utah. Oregon Grape. Poisonous Plants. 2022.

  6. Buttolph, Lita & Jones, Eric. Oregon Grape Root: A Brief Introduction to Harvesting and Marketing Oregon Grape as a Medicinal Herb from Small Private forestlands in the Pacific Northwest. USDA. 2012. DOI:10.13140/RG.2.1.5049.7048.

  7. Cicero AF, Baggioni A. Berberine and Its Role in Chronic DiseaseAdv Exp Med Biol. 2016;928:27-45. doi:10.1007/978-3-319-41334-1_2

  8. NIH. Goldenseal.

Additional Reading

By Dawn Sheldon, RN
Dawn Sheldon, RN, is a registered nurse and health writer. She is passionate about sharing her knowledge and empowering others.