The uva ursi plant is a low-lying evergreen bush whose berries are a favorite of bears, hence the name "bearberry." However, it is the leaves that are used medicinally.

Uva ursi has a long history of use for treating urinary conditions in both America and Europe. Up until the development of sulfa antibiotics, its principal active component, arbutin, was frequently prescribed as a urinary antiseptic.

Uva ursa is widely marketed today for the treatment of bladder infections. However, it has not been proven effective for this condition, and there are significant safety concerns with its use.5

What Is the Scientific Evidence for Uva Ursi?

Despite uva ursi's popularity for treating bladder infections, there is no meaningful evidence that it works. Two studies evaluated the antibacterial power of the urine of people who were taking uva ursi and found activity against most major bacteria that infect the urinary tract.6,7 However, while such findings are interesting, what is really needed is a double-blind, placebo-controlled trial to discover whether use of uva ursi actually helps people with established urinary tract infections. Unfortunately, not a single study of this type has been reported.

Rather strangely, one study evaluated continuous use of uva ursi for prevention of bladder infections. This double-blind, placebo-controlled trial followed 57 women for one year.8 Half were given a standardized dose of uva ursi (in combination with dandelion leaf, intended to promote urine flow), while the others received placebo. Over the course of the study, none of the women on uva ursi developed a bladder infection, whereas 5 of the untreated women did. However, this study is little more than a curiosity because most experts do not believe that continuous treatment with uva ursi is safe! (See Safety Issues below.)

Dosage

European recommendations indicate that the dosage of uva ursi should be adjusted to provide 400 to 800 mg of arbutin daily.9,10,11 Due to fears of toxicity (see Safety Issues below), this dosage should not be exceeded; furthermore, the herb should not be used for more than 2 weeks, and no more than 5 times a year.9

Uva ursi should be taken with meals to minimize gastrointestinal upset. Uva ursi (based on its arbutin content) is thought to be most effective in alkaline urine,2,3 and, for this reason, it should not be combined with vitamin C or cranberry juice. Some herbal experts recommend taking it along with calcium citrate to alkalinize the urine.

Uva ursi is also frequently sold in combination with other herbs traditionally thought to be helpful for bladder infections, including dandelion, cleavers, juniper berry, buchu, and parsley.

Safety Issues

There are significant safety concerns with uva ursi. The arbutin contained in uva ursi leaves is broken down in the intestine to another chemical, hydroquinone. This is altered a bit by the liver and then sent to the kidneys for excretion.1 Hydroquinone then acts as an antiseptic in the bladder. Unfortunately, hydroquinone is also a liver toxin, carcinogen, and irritant.12-15 For this reason, uva ursi is not recommended for long-term use. In addition, it should not be taken by young children, pregnant or nursing women, or those with severe liver or kidney disease.