Scientific Name: Uva Ursi
Other Names: Arberry, Arctostaphylos uva-ursi, Bear Grape, Bearberry, Coralillo, Hogberry, Kinnikinnick, Mealberry, Mountain Cranberry, Rockberry, Sandberry

Who is this for?

Uses

Uva ursi contains chemicals, primarily hydroquinone and hydroquinone derivatives, that make it potentially useful for urinary conditions. It has been approved for treating inflammation of the lower urinary tract by Commission E of the German Federal Institute for Drugs and Medical Devices, which is the German governmental agency that evaluates the safety and effectiveness of herbal products. The United States does not have a comparable agency to evaluate herbal products. Several chemicals found in uva ursi have antibacterial, antiseptic, and astringent properties that may also help to treat urinary tract infections. An astringent shrinks and tightens the top layers of mucous membranes, thereby reducing secretions, relieving irritation, and improving tissue firmness. The antibacterial action of uva ursi is diminished or destroyed, however, if the urine has too much acid in it. Formerly, uva ursi was also thought to promote the production of urine by the body, but this diuretic effect has not been proved in studies of humans. In general, prescription drugs that are more effective than uva ursi and that may have fewer side effects are available for treating urinary tract infections.

Even though tannins are thought not to be absorbed from the gastrointestinal tract, liver damage has occurred rarely in individuals who took large oral doses of tannins. Although uva ursi has not been studied specifically and no cases in which uva ursi caused liver damage have been reported, it does contain significant quantities of tannin. Oral uva ursi should be used with caution and its component, hydroquinone, which was formerly sold for topical use, should never be taken orally. Individuals with liver conditions should not take uva ursi. Furthermore, children are more likely to suffer liver damage from uva ursi, so it should not be given to children under the age of 12 years.

Chemicals in uva ursi may cause tightening of the uterus, which could potentially cause a miscarriage in pregnant women. These chemicals may also induce early labor and cause delivery to proceed rapidly. Therefore, pregnant women should avoid uva ursi.

Individuals who have kidney diseases or stomach conditions should avoid taking uva ursi due to possible irritation from chemicals it contains.

Precautions

Not enough is known about how uva ursi might affect an infant to recommend its use while breast-feeding.

What side effects should I watch for?

Major Side Effects

One case has been reported of permanent damage to the retina that apparently was caused by taking uva ursi for a long period of time (3 years). Chemicals in uva ursi are believed to interfere with retinal melanin, the black pigment that helps to disperse light and to protect the eyes. As a result, the individual’s vision was decreased and blurred.

In a dose of 6,000 mg (6 grams) or higher taken at one time, uva ursi may cause seizures or cyanosis (a blue tint to the skin caused by a lack of oxygen in the blood). Single doses of 30,000 mg (30 grams) or higher have been reported to cause death.

Other oral preparations that are high in tannin content have been associated with kidney or liver damage. Since uva ursi contains a relatively high percentage of tannins, using it may also present a risk for kidney or liver damage.

A case study of several individuals who regularly used large amounts of an oral product similar to uva ursi for many years, found that they had a higher incidence of tongue and lip cancer than expected. Cancers of the nose and esophagus may also be more likely in people who use large amounts of tannin-containing products for long amounts of time.

Less Severe Side Effects

Taking uva ursi has also been associated with:

• Brownish or greenish urine
• Nausea
• Ringing in the ears
• Upset stomach

What interactions should I watch for?

Prescription drugs such as ammonium chloride, non-prescription products such as vitamin C, herbals such as rose hips, and foods such as cranberry juice may all make the urine more acidic in nature. Potentially, taking a urine acidifier may lessen or destroy the antibacterial effects of uva ursi.

On the other hand, urinary alkalizers—drugs such as antacids, Bicitra, K-lyte, Polycitra, and sodium bicarbonate; herbals such as alfalfa and peppermint; and foods such as molasses, raisins, spinach, and some dried beans—reduce the acid levels in urine, which may increase uva ursi’s antibacterial effects. No cases of interactions specific to uva ursi have been reported in medical literature, but other oral products that contain tannins have interfered with the way the body uses certain drugs. Individuals who plan to take uva ursi should discuss all the prescription and non-prescription medicines they take with a doctor or pharmacist before they begin to use uva ursi.

Although no interactions have been reported between uva ursi and foods, the tannins in uva ursi may interfere with the absorption of minerals such as calcium, iron, and magnesium from foods. A dietary deficiency of these minerals is very rare in the United States, but it might be possible if large amounts of uva ursi are used continually and the diet is poor.

Some interactions between herbal products and medications can be more severe than others. The best way for you to avoid harmful interactions is to tell your doctor and/or pharmacist what medications you are currently taking, including any over-the-counter products, vitamins, and herbals. For specific information on how uva ursi interacts with drugs, other herbals, and foods and the severity of those interactions, please use our Drug Interactions Checker to check for possible interactions.

Should I take it?

As a plant, uva ursi generally stays small—only reaching a maximum height of about 2 feet, and often remaining as a ground cover under certain growing conditions. It grows slowly, but it thrives in areas such as canyon walls and rocky seacoasts that are hostile to other types of vegetation. Its small dark green leaves may turn a brownish color in the autumn, but they do not fall off the plant. White or pink flowers that bloom in the summer are followed by clusters of orange or red berries. Although the berries are edible for humans, they are not used much as food due to their somewhat bitter taste. They are said to attract bears, though, which may be why the plant was given the Latin name for "bearberry". Only the green leaves are harvested in the late summer or fall and dried for use in medicine. Native Americans are believed to have used dried uva ursi leaves like tobacco. In some countries, it has been used for tanning leather.

One of the chemical in uva ursi is hydroquinone, which was approved in 1982 by the U.S. Food and Drug Administration (FDA) as a topical agent for lightening freckles and other areas of darkened skin. Based on information from recent studies, however, the FDA has retracted approval and recommended that hydroquinone be removed from the market.

Dosage and Administration

Note: Because it has the potential to cause kidney, liver, or stomach damage, uva ursi should be taken no longer than 5 days at a time. Its oral use should be limited to only a few times a year, as well.

Although dosing for uva ursi varies, a commonly suggested dose range to treat urinary tract infections is 2,000 mg to 4,000 mg (2 grams to 4 grams) per day. Whether the recommended amounts of uva ursi actually reach high enough levels in the urine to be useful for treating urinary tract infections is questionable since the antibacterial action of uva ursi is diminished or cancelled when the urine has a high acid content. Many foods and beverages may make the urine acidic. However, bacteria usually need a low-acid (alkaline) environment, so they release a substance known as urease to lower the acid content of urine.

Tea may be made from uva ursi by soaking up to 3,000 mg (3 grams) of the dried leaves in about 5 ounces of cold water for at least 12 hours to decrease the amount of tannins. After the solid particles are strained out, the tea may be heated or consumed cold up to four times a day. In the past, cool uva ursi tea has also been used as a skin wash to treat mild skin infections.

Summary

The main use of uva ursi—to treat urinary tract infections—has been replaced by newer, more effective, and safer prescription drugs.

Risks

The high tannin content of uva ursi may cause kidney, liver, or stomach damage—especially for individuals who already have medical conditions of the kidney, liver or stomach. Higher rates of certain cancers may be attributed to high or long-term use of products containing tannins. These effects may be more likely for children under the age of 12 years more than they are for adults, so the use of uva ursi is not recommended for children or for breast-feeding women. Pregnant women may suffer a miscarriage, early onset of labor, or rapid delivery if they take uva ursi.

Side Effects

A single dose of 30,000 mg (30 grams) of uva ursi taken at one time has caused death. Single doses of 6,000 mg (6 grams) have been associated with seizures. Long-term use of uva ursi may damage vision permanently. Smaller doses may cause discolored urine, nausea, or ringing in the ears.

Interactions

Drugs or foods that acidify the urine may decrease the antibacterial effects of uva ursi, but urinary alkalizers (drugs or foods that reduce urine acid levels) may increase its antibacterial activity. The tannin content in uva ursi might interfere with the absorption of drugs and nutrients from food.

Last Revised July 18, 2007

References

Anon: Uva ursi. In: DerMarderosian A, Beutler JA, eds. Facts and Comparisons: The Review of Natural Products. St. Louis, MO, Facts and Comparisons. July 1997.

Beaux D, Fleurentin J, Mortier F. Effect of extracts of Orthosiphon stamineus Benth, Hieracium pilosella L., Sambucus nigra L. and Arctostaphylos uva-ursi (L.) Spreng. in rats. Phytotherapy Research. 1999;13(3):222-225.

Blumenthal M, Gruenwald J, Hall T, Rister RS, eds. The Complete German Commission E Monographs. Austin, Texas: American Botanical Council; 1998.

Federal Register 71:167 (August 29, 2006) 51146-51155.

Felter HW, Lloyd JU. King's American Dispensatory. Eighteenth Edition. Third Revision. Cincinnati, Ohio. Ohio Valley Co. 1898. Available at: http://www.ibiblio.org/herbmed/eclectic/kings/rctostaphylos.html. Accessed: October 31, 2003.

Grases F, Melero G, Costa-Bauza A, Prieto R, March JG. Urolithiasis and phytotherapy. International Urology and Nephrology. 1994;26(5):507-511.

Grieve M. Bearberry. In: A Modern Herbal. New York: Dover Publishers, 1971. Available at: http://www.botanical.com/botanical/mgmh/mgmh.html Posted 1995. Accessed October 14, 2003.

Haughton C. Arctostaphylos uva-ursi (Spreng.) Revised September 1, 2003. Available at: http://www.purplesage.org.uk/profiles/bearberry.htm. Accessed October 31, 2003.

Hoffmann DL. Bearberry. Herbal Materia Medica. No date given. Available at: http://www.healthy.net/asp/templates/article.asp?PageType=article&ID=1839. Accessed October 14, 2003.

Jellin JM, Gregory P, Batz F, Hitchens K, et al, eds. Pharmacist's Letter/Prescriber's Letter. Natural Medicines Comprehensive Database, 3rd Edition. Stockton CA: Therapeutic Research Facility, 2000.

Kruszewska H, Zareba T, Tyski S. Examination of antimicrobial activity of selected non-antibiotic drugs. Acta Pol Pharm. 2004;61(Suppl):18-21.

Madis Botanicals. Uva ursi PE 20%. Available at: http://www.pureworld.com/products/pdf_new/ursi.pdf. Accessed October 30, 2003.

Selje N, Hoffmann EM, Muetzel S, Ningrat R, Wallace RJ, Becker K. Results of a screening programme [sic] to identify plants or plant extracts that inhibit ruminal protein degradation. British Journal of Nutrition. 2007;98(1):45-53.

Sievers AF. Bearberry. In: The Herb Hunters Guide. Misc. Publ. No. 77. USDA, Washington D.C. 1930. Available at: http://www.hort.uconn.edu/plants/a/arcuva/arcuva1.html. Accessed October 14, 2003.

Viereck EG. Uva-ursi or kinnikinnick. Alaska Native Knowledge Network. University of Alaska, Fairbanks. Available at: http://www.ankn.uaf.edu/viereck/viereckuva.html. Accessed; October 14, 2003.

Wang L, Del Priore LV. Bull's-eye maculopathy secondary to herbal toxicity from uva ursi. American Journal of Ophthalmology. 2004;137(6):1135-1137.

Yarnell E. Botanical medicines for the urinary tract. World Journal of Urology. 2002;20(5):285-293.

Last Revised July 18, 2007

Note: The above information is not intended to replace the advice of your physician, pharmacist, or other healthcare professional. It is not meant to indicate that the use of the product is safe, appropriate, or effective for you.

In general, herbal products are not subject to review or approval by the U.S. Food and Drug Administration (FDA). They are not required to be standardized, meaning that the amounts of active ingredients or contaminants they contain may vary between brands or between different batches of the same brand. Not all of the risks, side effects, or interactions associated with the use of herbal products are known because few reliable studies of their use in humans have been done.

This information is provided for your education only. Please share this information with your healthcare provider and be sure that you talk to your doctor and pharmacist about all the prescription and non-prescription medicines you take before you begin to use any herbal product.

Back