Bilberry
In short
Summary of findings for quick reference
Dried bilberry fruit has a long European history of use. In 1938 Madaus identified Hildegard’s “Waltbeere” as bilberry; that identification is available here through a later account. His compilation also cites Renaissance herbals and Weinmann’s 1742 description of dried berries for diarrhoea. The sources concern different preparations and complaints, so they do not establish seven independent traditions of the same use.
There is no reliable evidence that bilberry improves night vision in healthy eyes. Canter and Ernst’s 2004 review found conflicting older results; the four most recent, methodologically rigorous randomised trials were negative. The RAF story is not evidence of a medicinal effect.
The 2015 EMA monograph on Myrtilli fructus siccus covers dried bilberries for mild diarrhoea and as a rinse for minor oral inflammation. This rests on longstanding traditional use, not sufficiently established clinical efficacy. The separate Myrtilli fructus recens monograph concerns a specific extract from fresh fruit for different complaints. Neither monograph applies to bilberry leaves.
Clinical evidence ↔ Historical significanceWe display two separate evidence categories: clinical evidence from modern trials and historical significance from documented healing tradition. Both are valuable, but they answer different questions.Read more
In every encyclopedia entry we evaluate two distinct categories of evidence. Clinical evidence as used in trials meets a narrower but scientifically essential bar. At the same time, the hundreds of thousands of plant species worldwide have only partially been captured and tested in modern studies.
Alongside the trial picture our researchers compile a comprehensive overview of where and since when a plant has been used across different traditions of natural medicine. When a plant has been used as a medicinal plant in many cultures across many generations, that historical significance deserves to be visible too.
Our position: a truly informative overview emerges only when both categories sit side by side. We communicate transparently what counts as what.
Overview
Bilberry (Vaccinium myrtillus), regionally called Schwarzbeere in Austria, is the small, dark fruit of a low shrub found in forests and mountain heaths. The European Medicines Agency (EMA) recognises traditional use of the dried fruit for mild diarrhoea and minor inflammation of the oral mucosa. Anthocyanins give the berries their colour; tannins account for their astringent properties.
A familiar story says that Royal Air Force pilots ate bilberry jam during the Second World War to improve night vision. Its origin and the suggestion that it concealed radar technology are uncertain. In Canter and Ernst’s 2004 systematic review, the most rigorous studies found no benefit for night vision in people with healthy eyes. The story therefore does not justify recommending bilberry preparations to improve normal night vision.
History
Bilberries have long been gathered in European forests. In Austria they are regionally known as Heidelbeere or Schwarzbeere and harvested in summer. Madaus’s 1938 account describes folk use for diarrhoea in Denmark, Norway, Hungary, Styria and Poland, among other places. Historical reports differ in plant part and preparation; not every mention refers to dried-fruit tea.
The night-vision story became associated with Royal Air Force pilots in the Second World War. The sources used here do not establish a British Air Ministry campaign to conceal a specific radar device. Historical recipes also require a distinction between fruit and leaf. Current EMA fruit monographs cannot be applied to leaf preparations.
Mechanism
Bilberry contains anthocyanins and tannins. Its pigments include glycosides of delphinidin, cyanidin, petunidin, peonidin and malvidin, whose antioxidant properties are studied in the laboratory. Tannins can bind proteins and have astringent properties. This offers a plausible explanation for traditional dried-fruit use in mild diarrhoea, but does not itself establish clinical benefit.
Proposed effects in the eye have included regeneration of the visual pigment rhodopsin and effects on small blood vessels. Such mechanisms do not establish improved night vision in humans. Likewise, antioxidant laboratory tests do not show what health benefit a bowl of berries or a cup of fruit tea provides.
Research includes constituents, inflammatory markers and night vision. In Karlsen and colleagues’ four-week randomised trial published in 2010, involving 62 participants at increased risk of cardiovascular disease, bilberry juice altered some inflammatory markers but did not differ from the control group in oxidative stress or antioxidant status. Canter and Ernst’s 2004 review assessed twelve placebo-controlled night-vision trials. The four most recent and rigorous studies found no benefit in healthy eyes.
These findings do not establish a general antioxidant health benefit or improved night vision. EMA bases dried-fruit use for mild diarrhoea and minor oral inflammation on longstanding experience with these preparations. Fresh fruit as food, medicinal dried fruit and concentrated extracts need to be assessed separately.
Evidence
| Outcome | Class | Grade | Effect | Studies | Refs |
|---|---|---|---|---|---|
| Mild diarrhoea (symptomatic relief)EMA lists dried bilberry fruit for mild diarrhoea as a traditional herbal medicinal product, based on longstanding use and plausible astringent activity; sufficient clinical efficacy data are lacking.Adults and adolescents aged 12 and over with mild diarrhoea | TraditionalTraditional use. Long-standing folk practice or EMA HMPC traditional-use monograph. | CEvidence quality grade C. Mixed or limited evidence. Small trials, signals, or traditional use under an EMA HMPC traditional-use monograph. This is an evidence rating, not a product endorsement. | Traditional Use | ||
| Minor inflammation of the oral mucosaEMA recognises a decoction of dried bilberries as a traditional mouth rinse for minor oral inflammation. This is based on longstanding use and plausible astringency, not sufficient clinical efficacy evidence.Adults and adolescents aged 12 and over with minor oral inflammation | TraditionalTraditional use. Long-standing folk practice or EMA HMPC traditional-use monograph. | CEvidence quality grade C. Mixed or limited evidence. Small trials, signals, or traditional use under an EMA HMPC traditional-use monograph. This is an evidence rating, not a product endorsement. | Traditional Use | ||
| Night vision in healthy eyesCanter and Ernst assessed twelve placebo-controlled trials in 2004. Some older studies reported positive results, but the four most recent and rigorous randomised trials found no benefit. Reliable evidence of improved normal night vision is lacking.Predominantly adults with healthy eyes | InsufficientInsufficient data. No reliable trials or traditional sources available. | DEvidence quality grade D. Preliminary signal. A single small trial, pilot result, or laboratory or animal model. Clinical relevance unclear. This is an evidence rating, not a product endorsement. | Mixed Effect | [1] | |
| Anthocyanin antioxidant activity (in-vitro and mechanistic)Antioxidant laboratory findings on bilberry constituents do not establish a human health benefit. In a four-week trial of 62 people at increased risk of cardiovascular disease, bilberry juice altered some inflammatory markers but did not change oxidative stress or antioxidant status relative to water control.Cell and laboratory studies; limited human marker work | EmergingEmerging research. Early small trials suggest an effect but await replication. | DEvidence quality grade D. Preliminary signal. A single small trial, pilot result, or laboratory or animal model. Clinical relevance unclear. This is an evidence rating, not a product endorsement. | In-Vitro Signal | [2] |
Usage
Forms and preparation
Medicinal dried-fruit tea is prepared as a decoction: simmer dried bilberries in water for about ten minutes, then strain. The fruit quantity and water volume depend on the intended use and package instructions. Fresh, washed berries can be eaten as food or made into pancakes, jam, syrup or compote. Use the stronger decoction specified for mouth rinsing after it has cooled. Use medicinal-quality dried fruit. Older recipes using bilberry leaves are not interchangeable alternatives: leaf preparations raise safety concerns, particularly at high doses or with prolonged use.
Dosage
For adults and adolescents aged 12 and over, EMA specifies a decoction of 5 to 15 grams of dried bilberries in 250 millilitres of water, three to four times daily for mild diarrhoea, totalling 15 to 60 grams daily. Mouth rinsing uses a different concentration: 20 grams in 200 millilitres of water, used several times daily. Follow medicinal tea package instructions. Seek medical advice if symptoms worsen, diarrhoea lasts more than three days, or oral symptoms last more than one week. These amounts apply to medicinal dried fruit, not bilberry leaves or concentrated extracts. Follow the instructions for each finished product. Fresh berries, jam and syrup are foods and are not equivalent to medicinal dried-fruit tea.
Safety
Look-alikes
Similar plants and look-alikes
Cultivated highbush blueberry (Vaccinium corymbosum)
Cultivated blueberries, including Vaccinium corymbosum cultivars, generally grow on larger shrubs and have larger fruit with pale flesh. They are edible. Medicinal information on Vaccinium myrtillus cannot automatically be applied to them.
Deadly nightshade (Atropa belladonna)
Deadly nightshade is highly poisonous. It bears glossy black berries with a star-shaped calyx and has much larger, entire leaves, whereas bilberry leaves are small and finely toothed. Do not rely on berry colour or plant height alone when foraging. Leave any plant you cannot identify confidently.
FAQs
When and how do you forage bilberries in the wild?
In Austria wild bilberries usually ripen from July to September, depending on altitude and weather. Collect only confidently identified plants. The low shrubs have green angular shoots and small, finely toothed leaves. A shallow bucket helps prevent lower berries from being crushed. Wash them before eating.
How do you prepare bilberry fruit tea?
For adults and adolescents aged 12 and over, EMA specifies a decoction of 5 to 15 grams of dried bilberries in 250 millilitres of water, three to four times daily for mild diarrhoea, totalling 15 to 60 grams daily. Mouth rinsing uses a different concentration: 20 grams in 200 millilitres of water, used several times daily. Follow medicinal tea package instructions. Seek medical advice if symptoms worsen, diarrhoea lasts more than three days, or oral symptoms last more than one week.
Is the night-vision story actually true?
A reliable benefit for night vision in healthy eyes has not been demonstrated. In Canter and Ernst’s 2004 review, the four most recent and rigorous studies were negative. The story about RAF pilots and bilberry jam is familiar, but its precise historical origin is uncertain. It does not justify recommending bilberry to improve night vision.
Can you confuse bilberry with anything dangerous in the forest?
Yes. Dark berries alone are not a safe identification feature. Highly poisonous deadly nightshade has glossy black fruit with a star-shaped calyx and much larger, entire leaves. Bilberry has small, finely toothed leaves on green angular shoots. Start with someone skilled in identifying the plants. Do not taste unknown berries; leave them if uncertain.
2 sources.
- Canter PH, Ernst E. Anthocyanosides of Vaccinium myrtillus (bilberry) for night vision--a systematic review of placebo-controlled trials. 2004. doi:10.1016/j.survophthal.2003.10.006
- Karlsen A et al.. Bilberry juice modulates plasma concentration of NF-kappaB related inflammatory markers in subjects at increased risk of CVD. 2010. doi:10.1007/s00394-010-0092-0
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