Uva ursi (Arctostaphylos uva-ursi), also known as bearberry, is an evergreen plant that grows throughout Europe and much of the United States. Traditionally it has been used to treat urinary tract infections, diarrhea, dysentery, and, among folk medicine practitioners, bronchitis.
The main active ingredients in uva ursi are the glycosides arbutin and methylarbutin. Once inside the body, these substances are transformed in the intestinal tract into hydroquinone, which has potent antibacterial properties. A report in a 2008 article in the Alternative Medicine Review notes that uva ursi can be effective at the first sign of urinary tract infection and for short-term prevention. (Head 2008) Previous research supported the ability of uva ursi to increase urinary flow in lab animals. (Beaux 1999) In yet another study, uva ursi was one of several herbal substances evaluated for its ability to prevent and treat urolithiasis (kidney and bladder stones). (Grases 1994)
Uva ursi helps to soothe and strengthen the membranes of the urinary tract. Research indicates that the herb is more effective if the urine is alkaline, which is achieved if you eat mainly a plant-based diet. The dried herb is available in capsules, with a suggested dose of 2 to 4 grams daily standardized to 400 to 800 mg of arbutin. (University of Maryland) Uva ursi should not be taken for more than five days at a time, and it should not be taken with vitamin C or orange juice. Side effects may include mild nausea, vomiting, irritability, and insomnia.
Beaux D et al. Effects of extracts of Orthosiphon stamineus Benth Hieracium pilosella L, Sambucus nigra L, and Arctostaphylos uva-ursi (L) Spreng in rats. Phytother Res 1999 May; 13(3): 222-25
Grases F et al. Urolithiasis and phytotherapy. Int Urol Nephrol 1994; 26(5): 507-11
Head KA. Natural approaches to prevention and treatment of infections of the lower urinary tract. Altern Med Rev 2008 Sep; 13(3): 227-44.
University of Maryland Medical Center: http://www.umm.edu/altmed/articles/uva-ursi-000278.htm