Uva Ursi is an evergreen shrub of which the leaves have been used traditionally as a remedy for urinary tract infections. It is also known as bearberry.
It is traditionally used as a tea or tincture, but also available in capsule form. I have previously listed it in natural antibiotics, but today I would like to take a closer look at how it’s used and what evidence we have behind its usage.
What is Uva Ursi used for
Uva Ursi is primarily used for urinary tract disorders, including [1]:
- Infections of the bladder, kidneys and urethra
- Inflammation of the urinary tract
- Increased urination
- Painful urination
- Urine containing excess acids (e.g. uric acid)
- Constipation
- Bronchitis
How Uva Ursi works
Uva ursi’s proposed mode of action is that it has antimicrobial properties and may help fight pathogenic bacteria in the bladder.
Further, it has been suggested that it may help with inflammation and may have a drying (astringent) effect on tissue [1].
These effects are credited to some of its chemical compounds, primarily arbutin and also tannins, including ellagic and gallic acid, as well as flavonoids such as quercetin.
The Evidence behind Uva Ursi
Uva Ursi has been used as a medicinal herb since the Middle Ages, however I could not find any recent clinical trials to support its use, which is unfortunately often the case for natural compounds (probably because of the lack of financial interest). However, a clinical trial comparing Uva Ursi with Ibuprofen for UTIs is underway [2] and I’m curiously awaiting the outcome.
The papers we do have are a bit old, but that doesn’t always mean they aren’t valid.
A German paper from 1970 summarized what evidence we had for Uva Ursi to date (and unfortunately we haven’t had much since) [3]:
- Uva ursi’s use for other purposes than that of an antiseptic for the urinary tract have not been proven to date or are mechanistically likely. A diuretic effect could not be shown in animal studies, in fact they showed a reduction of urinary output. However, a study from 1999 did show a diuretic effect in rats [4].
- The chemical responsible for antiseptic properties is hydroquinone, which in turn is a breakdown product of arbutin found in uva ursi. However, initial experiments with animals and humans have not found considerable amounts of hydroquinone in the urine after high intake of arbutin itself. The amount of arbutin contained in extracts of uva ursi would be even lower, and therefore the amount of the active antiseptic ending up in the urine is questionable.
- An antimicrobial effect of hydroquinone against, for example, E. coli bacteria would require a concentration of 1000 μg/ml, whereas the amount present after using uva ursi tea would probably only be around 10-20 μg/ml.
- Further experiments by the author of the paper have shown that the active chemical did not really show up in urine after taking uva ursi and no significant antimicrobial activity against pathogens took place in the urine.
- However, when alkalinity of the urine was increased antimicrobial activity could be shown in the urine. This is because the alkalinity is needed to generate the active form of hydroquinone (the antiseptic chemical).
To summarize: Uva ursi may be effective as an urinary antiseptic if a) the arbutin content of the product is high enough, and b) the urine is alkaline.
A small clinical trial from 1993 on the prophylactic effect of uva ursi on UTIs showed reduced rates of UTIs compared to a placebo [5].
So as you can see, the evidence is not actually overwhelming.
Adverse Effects
Generally, uva ursi seems to be well tolerated in small dosages (although I’ve spoken to people who couldn’t tolerate it at all).
However, there can be side effects such as gastrointestinal upset, especially when higher dosages of the plant are being taken in. Anything above 5 grams of uva ursi can cause serious side-effects.
The plant may be safe when used short-term, up to 1 month.
Long-term, uva ursi can have some serious side-effects and it also should never be given to children or pregnant women.
Conclusion
There seem to be many unknowns about uva ursi. Is it actually effective and what dose do we need to make it effective?
There seems to be no consensus on effective dosage and it seems that a higher dosage, which seems to be needed to get enough of the active compound, is not very safe (at least not long-term).
With that in mind, uva ursi would not be my preferred herb to use. There are others that are safer and probably more effective.
But as with anything, some people may well have had success with it, so I’m not writing this to discredit anyone’s experience.
What is your experience with uva ursi? Let me know in the comments!
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Sources
Trc Natural Medicines Database Uva Ursi September 2018 https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=350
- Trc Natural Medicines Database Uva Ursi September 2018 https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=350
- Trill J et al Uva-ursi extract and ibuprofen as alternative treatments of adult female urinary tract infection (ATAFUTI): study protocol for a randomised controlled trial. 2017 Sep 8;18(1):421. https://www.ncbi.nlm.nih.gov/pubmed/28886751
- Frohne, D. (1970). UNTERSUCHUNGEN ZUR FRAGE DER HARNDESINFIZIERENDEN WIRKUNGEN VON BÄRENTRAUBENBLATT–EXTRAKTEN1. Planta Medica, 18(01), 1–25. doi:10.1055/s-0028-1099743
- Beaux, D., Fleurentin, J., and Mortier, F. Effect of extracts of Orthosiphon stamineus Benth, Hieracium pilosella L., Sambucus nigra L. and Arctostaphylos uva-ursi (L.) in rats. Phytother.Res 1999;13(3):222-225. https://www.ncbi.nlm.nih.gov/pubmed/10353162?dopt=Abstract
- Larsson B, Jonasson A, Fianu S. Prophylactic effect of UVA-E in women with recurrent cystitis: a preliminary report. Curr Ther Res 1993;53:441-3. https://www.researchgate.net/publication/246197568_Prophylactic_effect_of_UVA-E_in_women_with_recurrent_cystitis_A_preliminary_report
