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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your healthcare provider before using herbs, especially if you are pregnant, nursing, taking medications, or have a medical condition.
Bilberry works primarily through its high concentration of anthocyanosides, which are potent flavonoid antioxidants. These compounds protect the retina from oxidative stress and improve microcirculation in the capillaries of the eye. Additionally, anthocyanosides assist in the regeneration of rhodopsin, a purple pigment in the retina essential for night vision and low-light adaptation.
Does bilberry interact with blood thinners or diabetes medications?
Yes, bilberry has potential interactions. Because anthocyanosides possess mild anticoagulant properties, taking bilberry with blood thinners like warfarin or antiplatelet drugs may increase bleeding risk (Evidence Level B). Furthermore, bilberry can lower blood sugar levels; combining it with diabetes medications requires careful monitoring to avoid hypoglycemia. Always consult a doctor before combining supplements with prescription medications.
What is the recommended dosage for bilberry extract?
The standard adult dosage for bilberry is 80-160 mg of a standardized extract, taken two to three times daily (Evidence Level B). This extract should be standardized to contain 25% anthocyanosides to ensure therapeutic potency. For general circulatory support or maintenance, lower doses may be sufficient, but consistency is key for achieving desired benefits.
Is bilberry safe to take during pregnancy?
Bilberry is generally considered safe during pregnancy when consumed in food amounts or taken at recommended dosages (Evidence Level C). No significant adverse effects have been reported in traditional use. However, due to the lack of extensive clinical trials specifically on pregnant women, it is best to consult a qualified healthcare provider or midwife before using bilberry supplements during pregnancy or breastfeeding.
Does bilberry actually improve night vision?
While bilberry is famous for the World War II pilot story regarding improved night vision, scientific evidence is mixed (Evidence Level B). Some studies indicate that anthocyanosides may accelerate the regeneration of rhodopsin, potentially aiding visual adaptation to darkness. However, rigorous clinical trials have not consistently confirmed these benefits in healthy subjects, though it remains widely used for eye strain and retinal health.
What are the side effects of taking bilberry?
Bilberry is generally well-tolerated, but some users may experience mild side effects such as gastrointestinal upset, diarrhea, dizziness, or headaches (Evidence Level C). Due to its mild blood-thinning effects, high doses may increase the risk of bleeding or bruising. Individuals with bleeding disorders or those preparing for surgery should exercise caution and discontinue use beforehand.
PubMed-compiled information sheet
This sheet was compiled from PubMed (NIH) abstracts using AI assistance. Every factual claim is cited to a real PubMed article (see the source list). It has not yet been human-reviewed — confirm with a healthcare provider before use.
Compiled from 27 PubMed articles · model: gemma4:31b
Summary
Bilberry (Vaccinium myrtillus) is a berry-bearing shrub rich in anthocyanins and tannins, used primarily for eye disorders and metabolic health [PMID:30000885, PMID:22593936].
Background
Vaccinium myrtillus L., commonly known as bilberry, is an economically important wild berry in Northern Europe that thrives in acidic, nutrient-poor soils [PMID:37836403, PMID:39339606].
Traditional uses
Bilberry has been used in European folk medicine to stop milk flow [PMID:30000885] and in traditional medicine for treating microvascular disorders, inflammatory conditions, and urinary system ailments [PMID:42229624]. Leaves are traditionally used in many countries to treat a variety of diseases [PMID:36678645], and fruits are used to treat non-specific diarrhea and symptoms related to varicose veins [PMID:33587635].
Active compounds
The fruit contains anthocyanins, tannins, phenolic acids, organic acids, coumarins, flavonols, flavanols, terpenoids, and volatile chemicals [PMID:30000885, PMID:36286028]. Leaves contain phenolic acids (notably chlorogenic acid), flavonoids (notably isoquercetin), and resveratrol [PMID:33809607].
Mechanism of action
Bilberry exerts anti-inflammatory effects by lowering expression of tumor necrosis factor-α, interleukin (IL)-6, and IL-1β, and by altering nuclear factor kappa B and Janus kinase-signal transducer and activator of transcription signaling pathways [PMID:36286028]. Its anthocyanins act as potent antioxidants [PMID:37836403]. Additionally, bilberry extracts may inhibit α-amylase, potentially decreasing postprandial blood glucose levels [PMID:37570789].
Clinical evidence
Evidence ANight Vision
Rigorous clinical studies do not support the hypothesis that V. myrtillus anthocyanosides improve normal night vision [PMID:14711439].
Evidence CType 2 Diabetes
Clinical studies on vision disorders and diabetes show contradictory results with no clear conclusion on benefits [PMID:35847049]. Animal and in vitro studies strongly indicate potential to ameliorate T2D, but appropriate clinical trials are needed [PMID:27748191].
Evidence CColorectal Cancer
Experimental studies indicate that bilberry inhibits colorectal cancer progression [PMID:34073356].
Evidence DDiabetic Kidney Disease
In mouse models, water-soluble anthocyanin-rich bilberry extract showed renoprotective effects by targeting ALOX15-mediated lipid peroxidation [PMID:42229624].
Safety & adverse effects
Bilberry preparations are generally well tolerated as food, but should be avoided by individuals allergic to bilberry, cranberry, blueberry, or other Vaccinium species [PMID:30000885].
Pregnancy & lactation
No data exist on the excretion of bilberry components into breastmilk or on the safety and efficacy in nursing mothers or infants; recommendations on using large quantities during breastfeeding cannot be made [PMID:30000885].
Drug interactions
In rats, bilberry extract significantly increased the activity of cytochrome P450 (CYP) 2C11 and CYP2E1 after 29 days of administration [PMID:31059744].
Evidence summary
The evidence is mixed. While preclinical (animal/cell) data strongly support anti-inflammatory, antioxidant, and metabolic benefits, rigorous clinical evidence for vision and diabetes is lacking or contradictory.
PubMed sources
1.PMID: 30000885 (2006) — [Vaccinium myrtillus]. · Archivos de la Sociedad Espanola de Oftalmologia
2.PMID: 36286028 (2022) — Anti-Inflammatory Activity of Bilberry (Vaccinium myrtillus L.). · Current issues in molecular biology
3.PMID: 37836403 (2023) — Vaccinium uliginosum and Vaccinium myrtillus-Two Species-One Used as a Functional Food. · Nutrients
4.PMID: 22593936 (2011) — Herbal Medicines in Glaucoma Treatment. · The Yale journal of biology and medicine
5.PMID: 39339606 (2024) — Bilberry Expansion in the Changing Subalpine Belt. · Plants (Basel, Switzerland)
— A Brief Review of Blue- and Bilberries' Potential to Curb Cardio-Metabolic Perturbations: Focus on Diabetes.
· Current pharmaceutical design
7.PMID: 42229624 (2026) — Water-soluble anthocyanins from Vaccinium myrtillus L. alleviate diabetic kidney disease by targeting ALOX15-mediated lipid peroxidation. · Journal of ethnopharmacology
8.PMID: 37570789 (2023) — Inhibitory Potential of Different Bilberry (Vaccinium myrtillus L.) Extracts on Human Salivary α-Amylase. · Molecules (Basel, Switzerland)
9.PMID: 36678645 (2022) — An Updated Systematic Review of Vaccinium myrtillus Leaves: Phytochemistry and Pharmacology. · Pharmaceutics
10.PMID: 33587635 (2021) — Quality Assessment of Bilberry Fruits (Vaccinium myrtillus) and Bilberry-Containing Dietary Supplements. · Journal of agricultural and food chemistry
11.PMID: 31059744 (2019) — Effect of bilberry extract (Vaccinium myrtillus L.) on drug-metabolizing enzymes in rats. · Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association
12.PMID: 40264677 (2025) — Vaccinium myrtillus L. ameliorates diabetic nephropathy via modulating metabolites and gut microbiota in rats. · Frontiers in pharmacology
13.PMID: 34073356 (2021) — Anticancer Effects of Lingonberry and Bilberry on Digestive Tract Cancers. · Antioxidants (Basel, Switzerland)
14.PMID: 14711439 (2004) — Anthocyanosides of Vaccinium myrtillus (bilberry) for night vision--a systematic review of placebo-controlled trials. · Survey of ophthalmology
15.PMID: 33809607 (2021) — Old Plant, New Possibilities: Wild Bilberry (Vaccinium myrtillus L., Ericaceae) in Topical Skin Preparation. · Antioxidants (Basel, Switzerland)
16.PMID: 35847049 (2022) — Bilberries: Curative and Miraculous - A Review on Bioactive Constituents and Clinical Research. · Frontiers in pharmacology
17.PMID: 32864929 (2020) — The Role of Vaccinium Myrtillus in the Prevention of Renal Injury in an Experimental Model of Ruptured Abdominal Aortic Aneurysm. · Brazilian journal of cardiovascular surgery