Uva Ursi
EricaceaeArctostaphylos uva-ursi
Also known as: Bearberry, Kinnikinnick, Bear's Grape
clinical_notes Clinical Summary
Uva Ursi (Arctostaphylos uva-ursi) is the primary urinary antiseptic herb in Western herbal medicine, used for centuries for mild uncomplicated lower urinary tract infections.
Its key active constituent arbutin is hydrolyzed to hydroquinone in alkaline urine, exerting antimicrobial effects against E.
coli, Staphylococcus, and other common uropathogens.
Approved by the EMA as a traditional herbal medicinal product for short-term UTI symptom relief in adults, it must be used cautiously: treatment should not exceed 7–14 days, must be avoided in pregnancy, lactation, children under 12, and patients with renal or hepatic impairment.
Urine pH should be confirmed as alkaline for optimal efficacy.
Pregnancy Safety
Absolutely contraindicated in pregnancy. Arbutin metabolite hydroquinone has demonstrated fetal toxicity in animal studies. EMA HMPC, WHO, and ESCOP all explicitly contraindicate use in pregnancy. Do not use under any circumstances.
Lactation Safety
Contraindicated during breastfeeding. Hydroquinone may be excreted in breast milk and could harm the nursing infant. All major regulatory monographs (EMA, WHO, ESCOP) contraindicate use in lactation.
warning Contraindications
- Pregnancy (contraindicated)Theoretical
- Lactation / Breastfeeding (contraindicated)Theoretical
- Children under 12 years (contraindicated)Theoretical
- Kidney disease or impaired renal function (contraindicated)Theoretical
- Long-term use beyond 7–14 consecutive days (avoid)Theoretical
- Liver disease or hepatic impairment (avoid)Theoretical
- Concurrent use with acidifying agents (high-dose vitamin C, cranberry, ammonium chloride) (caution)Theoretical
vital_signs Clinical Profile
Primary Indications
- check_circle mild lower urinary tract infection
- check_circle urinary tract inflammation
- check_circle cystitis (mild, uncomplicated)
- check_circle urinary antisepsis
- check_circle recurrent UTI prophylaxis (short-term)
Therapeutic Actions
System Affinities
- check_circle urinary
- check_circle renal
labs Active Constituents
arbutin
hydroquinone
methyl arbutin
gallotannins
ellagitannins
quercetin
isoquercitrin
hyperoside
iridoid glycosides
allantoin
ursolic acid
oleanolic acid
beta-sitosterol
volatile oils
history_edu Traditional Use
No TCM data available for this herb yet.
Traditional Uses Across Healing Systems
While many herbs lack controlled clinical trials, centuries of traditional practice across cultures provide valuable insight into their therapeutic applications.
Leaves brewed as tea for urinary tract infections, kidney inflammation, and as a general urinary tonic; leaves smoked ceremonially (kinnikinnick) by some North American Indigenous peoples
Kinnikinnick (uva ursi) was one of the most widely used urinary herbs among Indigenous peoples of North America. Also used as a smoking herb in ceremonial contexts.
Urinary antiseptic and astringent for cystitis and urethritis; short-term treatment for mild uncomplicated UTI; urinary tract tonic for recurrent infections
Approved by German Commission E for lower urinary tract inflammation. EMA traditional herbal medicinal product for short-term UTI symptom relief in adults.
Used as a diuretic and urinary antiseptic in Unani medicine; astringent for kidney and bladder complaints
Known as enab edhdhib in Arabic tradition; used in classical Unani practice for urinary tract conditions.
spa Parts Used
leaf
- urinary tract infection (mild, uncomplicated)
- urinary tract inflammation
- cystitis
- urinary antisepsis
ONLY the leaves are used medicinally — not the berries. Leaves standardized to arbutin content (minimum 7% by EMA standard). Available as dried leaf tea, standardized extract capsules, or tincture. Requires alkaline urine for efficacy; avoid concurrent vitamin C or acidifying agents. Limit use to maximum 7–14 consecutive days.
shield Safety
Contraindications — Evidence Basis
Pregnancy
Arbutin metabolite hydroquinone has demonstrated fetal toxicity in animal studies at higher doses. EMA HMPC monograph, ESCOP, and WHO monographs explicitly contraindicate use in pregnancy. Absolute contraindication.
Lactation / Breastfeeding
Hydroquinone (active urinary metabolite) may be excreted in breast milk and poses potential risk to the nursing infant. EMA and WHO monographs contraindicate use during lactation.
Children under 12 years
Safety in children has not been established. EMA and regulatory bodies contraindicate use in children under 12.
Kidney disease or impaired renal function
Hydroquinone is nephrotoxic at high concentrations and is primarily renally excreted. Contraindicated in renal insufficiency due to accumulation risk and irritant effect on inflamed kidney tissue.
Long-term use beyond 7–14 consecutive days
Prolonged use can lead to hepatotoxicity and nephrotoxicity from hydroquinone accumulation. EMA recommends no more than 1 week of use at a time, and no more than 5 courses per year.
Liver disease or hepatic impairment
Hydroquinone has potential hepatotoxic effects at elevated exposures. Avoid in patients with known liver disease.
Concurrent use with acidifying agents (high-dose vitamin C, cranberry, ammonium chloride)
Arbutin requires alkaline urine to release active hydroquinone metabolites. Acidifying agents reduce urinary pH and diminish therapeutic efficacy. Avoid concurrent high-dose vitamin C supplementation during treatment.
Monitoring Parameters
Monitor during use, especially with prolonged or high-dose therapy.
Liver enzymes (ALT, AST, bilirubin)
Baseline; repeat if use extends beyond recommended duration or symptoms developHydroquinone (released from arbutin) has hepatotoxic potential at elevated exposures; chronic use beyond recommended limits poses hepatotoxicity risk
flagThreshold: ALT or AST >2x upper limit of normal: discontinue immediately and investigate
Urine pH
At initiation of therapyArbutin is hydrolysed to active hydroquinone metabolites only in alkaline urine (pH >7); acidic urine significantly reduces antimicrobial efficacy
flagThreshold: Urine pH <6.5: consider alkalinising agent (e.g., sodium bicarbonate) or reconsider suitability of uva ursi
Toxicity
Acute overdose: >1g hydroquinone equivalents. Chronic: >1 week daily use
Acute overdose: nausea, vomiting, tinnitus, shortness of breath, seizures, collapse, delirium. Chronic high-dose: hepatotoxicity, nephrotoxicity, retinal thinning. Tannin-induced nausea at therapeutic doses
Discontinue immediately. For acute overdose, contact Poison Control. Symptomatic and supportive care. Hepatic and renal function monitoring. No specific antidote.
Adverse Effects
CYP Metabolism
In vitro evidence suggests uva ursi extracts may inhibit UGT1A1 (UDP-glucuronosyltransferase) and certain CYP450 isoenzymes including CYP1A2. Clinical significance unclear but caution warranted with narrow therapeutic index drugs. See Park JB et al. Food Chem Toxicol. 2018;120:651-661 and Chauhan B et al. Can J Physiol Pharmacol. 2007;85(11):1099-107.
swap_horiz Interactions
Lithium
Class: Mood Stabilizer
Uva ursi has diuretic properties that increase urine output. Diuresis can reduce renal lithium excretion, elevating serum lithium levels. As lithium has a very narrow therapeutic index, even modest increases in plasma concentration can lead to toxicity including tremor, confusion, cardiac arrhythmia, and renal failure.
Avoid uva ursi in patients on lithium therapy. If used, monitor serum lithium levels closely. Educate patients on lithium toxicity symptoms. Advise patients on lithium to report any new herbal supplement use immediately.
NSAIDs and Corticosteroids
Class: Anti-inflammatory
Uva ursi tannins and arbutin have anti-inflammatory properties that may be pharmacodynamically antagonistic to NSAIDs, but combined use may also exacerbate renal stress. Animal studies show uva ursi extracts modulate dexamethasone and prednisolone immune-inflammatory pathways, suggesting potential pharmacodynamic interactions.
Use with caution alongside NSAIDs due to potential additive renal stress and risk of GI irritation. Avoid prolonged high-dose combinations. Uva ursi should not be used for longer than 5 days due to hydroquinone toxicity risk.
Immunosuppressants
Class: Immunosuppressant
Uva ursi possesses immunostimulatory activity mediated by arbutin-derived hydroquinone and tannin constituents. These may antagonize the pharmacological effect of immunosuppressive drugs when co-administered, potentially increasing rejection risk in transplant patients.
Avoid uva ursi in patients receiving immunosuppressive therapy for organ transplant or autoimmune disease. The short-term use limitation (maximum 5 days) further limits its practical utility in these patients.
Drugs Requiring Alkaline Urine
Class: Various
Uva ursi is most effective as a urinary antiseptic in alkaline urine (pH >6.8), as arbutin must be hydrolyzed to antimicrobially active hydroquinone in alkaline conditions. NSAIDs, ascorbic acid supplements, and acidic foods lower urinary pH, antagonizing uva ursi's mechanism of action. Conversely, alkalinizing agents enhance its activity.
Advise patients taking uva ursi to avoid acidifying foods and medications (vitamin C, ammonium chloride, NSAIDs) during a course of uva ursi. Sodium bicarbonate or alkaline diet may enhance efficacy. Duration should not exceed 5 days.
UGT1A1 Substrates
Class: Various
In vitro studies identified uva ursi extracts as inhibitors of UGT1A1 (UDP-glucuronosyltransferase 1A1), an important phase II conjugation enzyme. Inhibition of UGT1A1 could reduce glucuronidation of substrate drugs including irinotecan (active metabolite SN-38), estrogens, and bilirubin, potentially increasing toxicity.
Exercise caution when uva ursi is used alongside UGT1A1 substrates, especially irinotecan in oncology patients. Monitor for signs of increased toxicity. The short-term use recommendation for uva ursi (max 5 days) limits the duration of this interaction.
Warfarin
Class: Anticoagulant
Uva ursi contains tannins with astringent effects and ursolic acid, which have shown anti-inflammatory activity. The ATAFUTI clinical trial specifically excluded patients on warfarin from uva ursi treatment, acknowledging an interaction concern. In vitro inhibition of UGT1A1 by uva ursi may also affect warfarin glucuronidation. The diuretic effect can alter drug distribution.
Patients on warfarin should avoid uva ursi. The ATAFUTI trial explicitly listed warfarin use as an exclusion criterion. Monitor INR if concurrent use is identified.
hub Combinations
Synergistic pairings can enhance therapeutic outcomes, while knowing suitable substitutes helps when specific herbs are unavailable or contraindicated.
No combination data available yet.
science Studies
Bearberry in the treatment of acute uncomplicated cystitis (BRUMI): protocol of a multicentre, randomised double-blind clinical trial
RCTThe BRUMI trial is a multicentre, randomised, double-blind, placebo-controlled non-inferiority trial assessing bearberry (Arctostaphylos uva-ursi) leaf dry extract tablets versus fosfomycin (standard antibiotic) for acute uncomplicated cystitis in premenopausal women. Eligible patients with typical cystitis symptoms scored ≥6 on the Acute Cystitis Symptom Score are randomised 1:1. The primary endpoint is improvement of symptoms at day 7, with secondary endpoints including bacteriuria, recurrence at 90 days, and safety. This is the first trial designed to formally establish non-inferiority of uva-ursi against standard antibiotic therapy, which would support it as an antibiotic-sparing strategy.
Reducing antibiotic use for uncomplicated urinary tract infection in general practice by treatment with uva-ursi (REGATTA) - a double-blind, randomized, controlled comparative effectiveness trial
RCTThe REGATTA trial is a double-blind, randomised, controlled comparative effectiveness trial comparing initial treatment with Arctostaphylos uva-ursi (bearberry extract arbutin, 3×2 arbutin 105mg for 5 days) against fosfomycin (antibiotic) in women aged 18–75 with suspected uncomplicated UTI. The primary co-outcomes were total antibiotic courses within 28 days and symptom burden over 7 days. The trial was designed to test whether uva-ursi could reduce antibiotic use without substantially increasing symptom burden or complication rates, addressing the important clinical challenge of antibiotic stewardship in primary care UTI management.
medication Dosing
tea
3g dried leaf (standardized to ≥7% arbutin) per cup
3–4x daily for maximum 7–14 days
Cold maceration (soak leaves in cold water for 12–24 hours rather than hot infusion) reduces tannin extraction and minimises GI irritation while preserving arbutin content. Drink with alkaline food or add sodium bicarbonate (1/4 tsp per litre water) to alkalinise urine for optimal arbutin-to-hydroquinone conversion. Do NOT take with vitamin C or cranberry juice. Do not use for more than 1 week per course; maximum 5 courses per year.
capsule
400–840 mg standardized extract (standardized to 20% arbutin, providing 80–168mg arbutin per dose)
3x daily (TID) for maximum 7–14 days
EMA-recommended standardized extract dosing equivalent to 400–840mg hydroquinone derivatives as anhydrous arbutin per day. Take with a full glass of water. Do not exceed recommended dose or duration. Alkaline urine is required for efficacy — avoid co-administration with vitamin C.
tincture
1:5 (25% alcohol): 3–5ml
3x daily (TID) for maximum 7–14 days
Tincture of dried bearberry leaf (1:5, 25% ethanol). Ensure tincture is made from standardized leaf material. Avoid concurrent use with cranberry juice (acidifying). Dilute well in water before taking to minimise gastric irritation from tannins.
Disclaimer: This information is largely AI-generated and reviewed by human experts at Evara Health. It is intended for educational and clinical reference purposes only and should not replace professional medical advice.
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