Uva ursi contains a considerable amount of tannins (up to 40 percent) making it one of natures most powerful astringents. Unlike most herbs which can have a wide range of uses, uva-ursi is a specialist in infections and inflammations of the urinary tract. Uva uris contains as assortment of chemical compounds, especially arbutin, that are active against many of the pathogens commonly found in urinary tract infections
The high tannin content of uva ursi can contribute to nausea and vomiting if you are sensitive. Do not use if your urine is already acidic. Uva usi is a strong herb that should be reserved for those times when a quick intervention is needed. It should not be taken for extended periods.