The plant Arctostaphylos uva ursi, also known as bearberry, was a traditional treatment for urinary tract infections and bladder inflammation, or cystitis, before the development of sulfa drugs and other antibiotics. Uva ursi leaf contains chemicals such as arbutin and hydroquinone, which have antibacterial properties, and tannins with astringent effects that reduce inflammation. The Commission E, the German regulatory agency for herbal products, has approved uva ursi for treating lower urinary tract inflammation. Uva ursi side effects are not common and most are mild, according to the University of Maryland Medical Center (UMMC), but the risk of severe side effects still calls for caution.
Most Common Effects
The most frequently reported uva ursi side effects are nausea, vomiting, insomnia and irritability, according to the UMMC. Herbwisdom.com explains that nausea caused by uva ursi is more likely in people with a sensitive stomach. High doses of uva ursi can cause a harmless green-brown urine discoloration.
Liver Problems
One uva ursi component, hydroquinone, can be harmful to the liver and may result in liver damage. The UMMC recommends that people take uva ursi for no longer than five days and do so under a doctor's supervision. No one should take uva ursi more than five separate times in one year, or exceed recommended doses. Signs of liver problems include dark urine, jaundice and fatigue.
High Dose Side Effects
Very high doses of 6 g or higher of uva ursi at one time can be toxic, as noted by Herbwisdom.com. Symptoms include vomiting, shortness of breath, ringing in the ears, seizures and cyanosis, which causes a blue tint in skin due to limited oxygen in the blood. Doses this high can be life-threatening.
Pregnancy Considerations
Pregnant women should not take uva ursi, particularly in large doses. Labels on uva ursi supplements and products containing uva ursi warn that the herb may cause uterine tightening or stimulate uterine contractions.
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