© Marek Silarski · CC BY-SA 3.0 · Commons
Vaccinium myrtillus
Heidelbeere · (Vaccinium myrtillus)
Heath family (Ericaceae)
Description
This heath-family berry only develops its medicinal action when dried, not fresh: fresh bilberries are simply a nutrient-rich fruit, while 5 to 10 grams of dried berries – chewed slowly or drunk as a decoction – help with mild, non-specific diarrhoea, a traditional use officially recognised by the EMA. The effect comes from condensed tannins (proanthocyanidins), which tighten the intestinal lining, slow fluid loss and act mildly antimicrobial; the same decoction also works as a gargle for inflamed mouth and throat tissue. Eating the berries temporarily stains teeth and lips bluish-violet – a side effect of their abundant anthocyanins, which also act as strong antioxidants. Fresh berries additionally supply vitamin C, vitamin E, quercetin and notably high manganese. Diarrhoea lasting beyond three to four days, fever or blood in the stool require medical care; the tannins should also be taken separately from iron supplements, as they can inhibit iron absorption.
CONTRAINDICATED for children
Medicinal use not under 12. Fresh berries as food are safe.
Classic self-care for mild non-specific diarrhoea: condensed tannins (proanthocyanidins) tighten intestinal mucosa, reduce fluid loss and are mildly antimicrobial.
Preparation & dosage
CHEW DRIED BERRIES: 5–10 g slowly, up to 3× daily. Only DRIED berries are astringent — fresh berries can be mildly laxative in large amounts. Do not continue beyond 3–4 days without medical advice.
- Dry amount
- 5–10 g
- Doses per day
- 3×
- Max duration
- 1 weeks
⚠ Age restriction: ≥ 12 years — Per EMA from 12 years. Diarrhoea in small children needs medical care.
Bilberry decoction for mild diarrhoea as alternative to direct chewing. Hot extraction dissolves tannins and anthocyanins from dried fruit flesh.
Preparation & dosage
DECOCTION: 5–10 g + 150–250 ml cold water, boil and simmer 10 min until berries swell. Strain (eat the berries too), drink lukewarm 2–3× daily. Lips and teeth temporarily stained blue-violet.
- Dry amount
- 5–10 g
- Doses per day
- 3×
- Max duration
- 1 weeks
⚠ Age restriction: ≥ 12 years — From 12 years.
Traditional mouth and throat rinse for mild oral mucosa inflammation, aphthae and gum irritation. EMA monograph confirms this indication as traditional use.
Preparation & dosage
DECOCTION as mouth rinse: 5–10 g + 150–250 ml water, simmer 10 min, strain, cool to lukewarm. Gargle or rinse 2–3× daily — spit out. Tannins act astringently on inflamed oral mucosa.
- Dry amount
- 5–10 g
- Doses per day
- 3×
- Max duration
- 1 weeks
⚠ Age restriction: ≥ 12 years — From 12 years.
Fresh bilberries as food and source of anthocyanins, vitamin C, vitamin E, quercetin, manganese and pectins. Antioxidant effects of anthocyanins well documented; medicinal indications only for dried berries.
Preparation & dosage
FRESH BERRIES: eat as fruit without medicinal restrictions. Rich in anthocyanins, vitamin C, vitamin E, quercetin and manganese. Fructose and pectins can be mildly laxative in large amounts.
Folk use of bilberry leaves for digestive complaints and traditionally described as blood-sugar lowering. Clinical evidence for blood glucose effect is insufficient; high tannin and arbutin content require caution.
Preparation & dosage
LEAF TEA: 2–3 g dried leaves (harvested late summer) + 250 ml boiling water, steep 10 min. Max 3 weeks due to high tannin content. CAUTION: leaves contain arbutin — potentially toxic in large amounts or prolonged use. Only in short-term courses after consultation.
- Dry amount
- 2–3 g
- Doses per day
- 2×
- Max duration
- 3 weeks
Only DRIED berries are astringent. Fresh bilberries are normal fruit — no antidiarrhoeal effect. Diarrhoea beyond 3–4 days, with fever or blood: doctor immediately. Dehydration risk in young children and elderly. Tannin decoctions: separate from iron supplements by 2 hours minimum. Bilberry leaves max 3 weeks (tannin/arbutin). Anticoagulants: caution (PFAF note).
⏱ Max continuous use: 1 weeks
Medicinal use not recommended in pregnancy. Fresh berries as food are unaffected.
Medicinal use not recommended. Fresh berries as food are safe.
Medicinal use not under 12. Fresh berries as food are safe.
Drug interactions
Eisenpräparate und Mineralstoff-Supplemente
Tannins form poorly soluble complexes with iron, calcium and zinc — reduced bioavailability. Separate by at least 2 hours.
Antikoagulantien (Cumarin-Derivate, z.B. Warfarin)
Possible additive or antagonistic interaction; PFAF advises caution with anticoagulant therapy. Clinical data limited.
Alkaloid-haltige Arzneimittel
Tannins may precipitate alkaloids in the intestine. Separate by 1–2 hours.
Contraindications
- Hypersensitivity to bilberries or other Vaccinium species.
- Children under 12 years (medicinal use).
- Persistent diarrhoea with fever, blood in stool or severe weakness — immediate medical care.
Harvested part: dried berries
- Time of day:
- Dry morning after dew has dried — wet berries mould rapidly.
- Drying:
- Harvest only fully ripe deep-blue berries. Do NOT wash before drying (destroys waxy bloom). Dry single-layer at 35–40 °C in oven (door ajar) or dehydrator until raisin-hard and wrinkled (ca. 1–2 days). Check for mould.
- Storage:
- 12 months — Airtight in dark jars, cool and dry. Check for mould before first use. At least 1 year shelf life.
- Time of day:
- Young, fully developed leaves before or at the onset of fruit ripening — not yet yellowing.
- Drying:
- Dry leaves individually or in small bundles at 30–40 °C in shade until dry and papery. Due to high tannin and arbutin content: use only in small amounts for short courses. Max duration 3 weeks.
- Storage:
- 12 months — Airtight, dark, dry. Use within 1 year.
- Kondensierte Gerbstoffe (Proanthocyanidine, Catechin, Epicatechin)TanninContent: 5–10 %Fruit
Main active compounds of the dried drug. Astringent, antimicrobial, antidiarrhoeal. Dominate in dried berries; fresh berries have significantly lower tannin concentration. A-type procyanidins particularly characteristic in V. myrtillus.
- Anthocyane (Delphinidin-, Cyanidin-, Petunidin-, Peonidin-, Malvidin-Glykoside)GlycosideContent: 0,5–1 %Fruit
15 major anthocyanins; delphinidin and cyanidin glycosides dominant ~1:1. Colour both flesh and skin (distinguishes V. myrtillus from cultivated blueberry). Strongly antioxidant. EMA monograph lists no eye indication — night vision effect not clinically established.
- Quercetin und Myricetin-GlykosideFlavonoidFruit
Quercetin accounts for over 50% of total flavonoids. Antioxidant, mildly anti-inflammatory.
- Chlorogensäure, Kaffeesäure (Caffeoylsäuren)Phenolic acidFruit
Antioxidant. Caffeoyl acids also found in the leaves.
- PektinePolysaccharideFruit
Soluble fibre — contribute to stool-regulating effect. Higher in fresh berries than dried.
- Vitamin C und Vitamin EVitaminFruit
Vitamin C ~30 mg/100 g fresh berry; vitamin E ~1.9 mg/100 g. Antioxidant contribution in fresh berries.
- ManganMineralFruit
Bilberries are among the most manganese-rich fruits.
- Iridoid-Glykoside (Vaccinosid)GlycosideFruit
Vaccinoside described as characteristic iridoid in V. myrtillus. Biological activity in fruits little researched.
- [1]MonographEMA/HMPC/678995/2013 — European Union herbal monograph on Vaccinium myrtillus L., fructus siccus (Final, 9 December 2015)(accessed: 2026-05-18)
- [5]MonographBilberries: Curative and Miraculous – A Review on Bioactive Constituents and Clinical Research (Vaněková & Rollinger, Frontiers in Pharmacology, 2022)(accessed: 2026-05-21)
- [4]BookPlants For A Future — Vaccinium myrtillus(accessed: 2026-05-21)
- [2]WikipediaHeidelbeere (Wikipedia DE)(accessed: 2026-05-21)
- [3]WikipediaVaccinium myrtillus (Wikipedia EN)(accessed: 2026-05-21)