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Fraxinus excelsior
CautionGemeine Esche · (Fraxinus excelsior)
Olive family (Oleaceae)
Description
At up to 40 metres, common ash is among Europe's tallest broadleaf trees; on windy, exposed sites it stops at 15 to 20 metres. It is marked by pinnate leaves of usually nine to thirteen leaflets, which drop in autumn while still green, and by strikingly velvet-black winter buds. Botanically it belongs to the olive family and is thus related to olive and lilac. The leaves, gathered in May and June, are the part used; they contain oleuropein, rutin and the coumarins fraxin and fraxetin. In European folk medicine a leaf tea serves as a diuretic and traditionally for mild joint complaints, while the mannitol it contains has a gentle laxative effect. Such a flushing tea is unsuitable for anyone with heart or kidney weakness. For some decades now, ash dieback has threatened populations across much of Europe.
Ash leaf tea has traditionally been used in European folk medicine for mild joint complaints and rheumatic conditions. The anti-inflammatory activity is attributed to the interplay of secoiridoids (oleuropein, ligstroside), flavonoids (rutin), and hydroxycinnamic acids. The EMA/HMPC monograph (EMA/HMPC/239271/2011) classifies this indication as traditional use.
Preparation & dosage
Pour 150 ml of boiling water over 1.5–5 g of dried, chopped ash leaves, steep for 10 minutes, then strain. Drink up to 3 cups daily.
- Dry amount
- 1.5–5 g
- Doses per day
- 3×
Ash leaf tea is traditionally used as an aquaretic to support kidney function and for mild urinary tract complaints. Mannitol and potassium salts in the leaves promote diuresis. The EMA/HMPC monograph lists this indication as a traditional herbal use.
Preparation & dosage
Steep 1.5–5 g of dried ash leaves in 150 ml boiling water for 10 minutes. Ensure adequate fluid intake (at least 2 litres per day).
- Dry amount
- 1.5–5 g
- Doses per day
- 3×
Alcoholic extract of young ash branch bark was used in folk medicine for joint rheumatism and fever. The bark contains higher levels of iridoid bitters and coumarins (fraxin, fraxetin, esculin) than the leaves.
Preparation & dosage
Ready-made preparation or 1:5 tincture (40–60 % ethanol): 50 drops up to 3 times daily, not longer than 4 weeks without medical consultation.
- Doses per day
- 3×
In traditional folk medicine, ash leaves were used for their mild purgative effect in constipation and sluggish digestion. The mannitol content acts as an osmotic laxative. This use is not scientifically validated.
Preparation & dosage
Steep 2–4 g dried leaves in 200 ml hot water for 10 minutes. Drink in the evening.
- Dry amount
- 2–4 g
- Doses per day
- 2×
Ash bark was historically used in Europe as a substitute for Peruvian bark (quinine) in intermittent fever (malaria-like conditions). The bitter iridoid glycosides have a tonic effect. This use is now obsolete and only of historical relevance.
Preparation & dosage
Simmer 2–5 g chopped ash bark in 250 ml water for 15 minutes, strain. Historical use only — always consult a doctor for fever.
- Dry amount
- 2–5 g
- Doses per day
- 2×
Fresh or steamed ash leaves were applied as moist compresses in folk medicine to poorly healing wounds, ulcers, and skin complaints. The tannin content acts as an astringent and mild antiseptic.
Full baths with concentrated ash leaf infusions were traditionally used for gout and rheumatic joint pain. The warmth and possible transdermal absorption of phenolic acids support local circulation.
Preparation & dosage
Boil 100 g dried ash leaves in 2 litres of water for 10 minutes, strain, and add to a bathtub (37–38 °C). Bathe for 15–20 minutes.
Sources: [7]
Do not use as a diuretic flush tea in cardiac or renal insufficiency (increased fluid intake contraindicated). Seek medical advice immediately for fever, blood in urine, painful urination, or swollen joints with fever. Known hypersensitivity to Oleaceae (olive, lilac) — cross-reactions possible.
⏱ Max continuous use: 4 weeks
No data on use during pregnancy and lactation. Avoid as a precaution.
No safety data available. Use during lactation not recommended.
No data for children under 12 years. Traditional use limited to adults.
Drug interactions
Diuretika
Additive diuretic effect possible; electrolyte losses (potassium) may be enhanced.
Contraindications
- Cardiac insufficiency or renal insufficiency (when used as an aquaretic)
- Known hypersensitivity to Fraxinus excelsior or other Oleaceae
Harvested part: young leaves, bark of young twigs
- Time of day:
- Morning after dew has dried
- Drying:
- Spread loosely and dry at 35–40 °C or in a well-ventilated, shaded location. Leaves must rustle before storage.
- Storage:
- 12 months — Store in well-sealed, dark glass jars or paper bags in a cool, dry place.
- Time of day:
- No time-of-day restriction; peel bark from young branches (2–4 cm diameter).
- Drying:
- Dry bark pieces at max. 40 °C. Bark is dry when it breaks cleanly.
- Storage:
- 24 months — Store dark, dry and well-sealed; woody scent serves as quality indicator.
- OleuropeinGlycosideContent: 0,5–2 %Leaf
Secoiridoid glycoside, characteristic compound of Oleaceae; inhibits pro-inflammatory cytokines (TNF-α, IL-6) in vitro.
- LigstrosidGlycosideLeaf
Further secoiridoid in ash leaves; shows anti-inflammatory activity by reducing IL-1β.
- Rutin (Rutoside)FlavonoidLeaf
Dominant flavonoid in ash leaves; antioxidant and capillary-stabilising.
- FraxinGlycosideBark
Coumarin glycoside of ash bark; anti-inflammatory and antioxidant properties.
- FraxetinOtherBark
Aglycone part of fraxin; coumarin derivative; inhibits lipoxygenase and acts as antioxidant. (Category 'other' as coumarins have no dedicated enum.)
- MannitolOtherContent: 0,5–1,5 %Leaf
Sugar alcohol in ash leaves and bark; responsible for the diuretic effect.
- Chlorogensäure / NeochlorogensäurePhenolic acidLeaf
Hydroxycinnamic acid derivatives in ash leaves; antioxidant, in vitro anti-inflammatory.
- TannineTanninBark
Hydrolysable and condensed tannins in bark and leaves; astringent and mildly antiseptic.
- [1]MonographEMA/HMPC Monograph: Fraxini folium — Final Community Herbal Monograph (EMA/HMPC/239271/2011)(accessed: 2026-05-22)
- [2]MonographSarfraz et al. (2017): Fraxinus — A Plant with Versatile Pharmacological and Biological Activities. Evidence-Based Complementary and Alternative Medicine, DOI 10.1155/2017/4269868(accessed: 2026-05-22)
- [3]MonographKołtun-Jasion et al. (2023): Bio-Guided Isolation of Compounds from Fraxinus excelsior Leaves with Anti-Inflammatory Activity. Int. J. Mol. Sci. 24(4):3750, DOI 10.3390/ijms24043750(accessed: 2026-05-22)
- [4]BookMaud Grieve: A Modern Herbal — Ash (Fraxinus excelsior), botanical.com(accessed: 2026-05-22)
- [5]BookKing's American Dispensatory: Fraxinus. Henriette's Herbal Homepage(accessed: 2026-05-22)
- [6]BookPlants For A Future (PFAF): Fraxinus excelsior(accessed: 2026-05-22)
- [7]BookArzneipflanzenlexikon: Ash (Fraxinus excelsior) — medicinal use, dosage, safety(accessed: 2026-05-22)