What Is Oregon Grape?

Oregon grape (Berberis aquifolium or Mahonia aquifolium) is a medicinal herb from the Berberidaceae plant family. Long ago, 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. It produces blackish-blue, unpleasant-tasting, edible berries that look like tiny grapes. 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 grows in the Pacific Northwest region of the United States—including Oregon— it flourishes in many other areas of the country.

This article discusses the uses of Oregon grape in traditional medicine and its side effects, interactions, and special precautions.

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 of 0.2 to 1 gram of berberine (an ingredient in Oregon grape) per day for up to three months, or as a topical cream, applied to the skin two to three times daily.
  • Safety Considerations: Pregnancy, breastfeeding, jaundice, newborn babies, children, allergies

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.

Oregon grape root has been used in herbal medicine to treat different disorders. Most of the published clinical research 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 ingredient in 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 suggest berberine improved insulin sensitivity and secretion, and other outcomes, like inflammation, in cell cultures of 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 generally considered 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

Common side effects identified in Oregon grape and berberine include:

  • 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, particularly too much berberine, may have severe effects, such as jaundice (yellowing of the skin) when taken in high doses.


Oregon grape is not recommended for pregnant or breastfeeding people 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 and, therefore, 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 insufficient data to determine an effective, safe dose of Oregon grape.

However, there are clinical studies on the oral consumption of berberine.

Berberine is an active ingredient in Oregon grape. A dose of 0.2 to one gram of berberine per day in tablet or capsule forms has safely 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.

Research regarding the excessive use of berberine is in its early stages and has only been conducted in animals. The known effective dose for humans is not known.

Speak with your healthcare provider about what dosage of Oregon grape would be best for you.


Certain medicines may interact with Oregon grape and interfere with the liver's ability to break down some medications. 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:

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

If the liver doesn't properly break down certain medications, they may have increased side effects.

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 safety, particularly when taking other medication. This includes prescription, herbal, over-the-counter (OTC), and nutritional/medicinal supplements.

Reading a supplement's ingredient list and nutrition facts panel is essential 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 and disposing of Oregon Grape can be found on the package.

The dried root of Oregon grape can be stored in food or pharmaceutical-grade polyethylene bags. 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 listed 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

Berberine is an alkaloid found in Oregon grape. Other supplements containing berberine (i.e., goldenseal) may have similar effects.

Some supplements similar to Oregon grape include:

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

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 evidence regarding its safety and effectiveness in humans. Speak to your healthcare provider before trying Oregon grape 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. 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 not thought to 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 a treatment for diabetes in humans. Speak with your healthcare provider about your diabetes treatment 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 they are all of the same quality.

Supplements of Oregon grape can be found in tincture and capsule forms.


Oregon grape is a medicinal plant with a history of use in the traditional medicine practices of Native Indian 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 its long-term effects, along with dosing limits.

Discuss dosing and safety considerations with a healthcare professional when taking Oregon grape. Oregon grape may interact with several medications and other supplements. Share with your healthcare provider all medicines 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. National Park Service. Oregon grape.

  2. Janeczek M, Moy L, Lake EP, et al. 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. Medline Plus. Berberine.

  5. Health University of Utah. Oregon grape.

  6. Buttolph L, Jones E. Oregon grape root: a brief introduction to harvesting and marketing oregon grape as a medicinal herb from small private forestlands in the pacific northwest. 2012. doi:10.13140/RG.2.1.5049.7048

  7. National Center for Complimentary and Integrative Health. Goldenseal.

  8. 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

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.