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Black Alder / European Alder (Alnus glutinosa)
Materia Medica
Family: Betulaceae
Botanical name: Alnus glutinosa (L.) Gaertn.
Common names: Black Alder, European Alder, Common Alder
Parts used: Bark, leaves
Growth habit: Deciduous tree
Primary traditions: European folk medicine
Actions & Energetics
Traditional European records describe the dried bark as astringent, alterative, and tonic. Fresh bark is noted as emetic. Leaves are astringent and have been used externally and for engorgement.
Botanical Description
Alnus glutinosa is a medium-sized deciduous tree with sticky young leaves that are elliptic to obovate and finely serrate. It produces male and female catkins and woody cones. It grows in wet soils along rivers and in marshes across Europe and parts of Asia and North Africa. Distinct from Alder Buckthorn (Frangula alnus).
Traditional Indications
European folk sources record a decoction of the dried bark as a gargle for sore throat and mouth inflammation, and as a wash for skin issues and swellings. Leaves have been applied as poultices for wounds and rheumatism. Hildegard of Bingen noted leaf poultices for knee pain. The tree is nitrogen-fixing and ecologically important in wet habitats.
Preparations & Dosage
Bark Decoction (External)
Dried bark is simmered and used as a gargle or wash for mouth, throat, and skin. Specific traditional gram amounts vary by region.
Leaf Poultice
Fresh or dried leaves applied externally to swellings and wounds.
Constituents
Bark contains tannins, diarylheptanoids (including oregonin), flavonoids, and terpenoids. These contribute to the astringent character.
Modern Research
Laboratory studies have examined antioxidant, antimicrobial, and anti-inflammatory effects of extracts. Human clinical data remain limited. The tree continues to be noted in ethnobotanical records.
Adverse Effects
Fresh bark can act as an emetic. Ordinary external use of dried material is the primary traditional application. Pollen can cause allergy in sensitive individuals.
Interactions & Contraindications
No clinically established major drug interactions are recorded for ordinary external or low traditional use.
Pregnancy & Breastfeeding
Historical sources note leaf use for engorgement. Modern data are limited. Ordinary external use is the more common traditional pattern.
Habitat & Cultivation
- Native range: Europe, western Asia, North Africa
- Habitat: Wetlands, riverbanks, marshes
- Cultivation: Planted for soil stabilization and nitrogen fixation
Harvesting & Drying
Bark is harvested from young branches in spring and dried. Leaves are gathered in summer. Dried bark is preferred for most traditional preparations.
History, Folklore & Spiritual Use
Black alder has a long record in European folk medicine as an astringent for mouth, throat, and skin. In Celtic tradition the tree was associated with protection. The wood was used for shields and the bark for dyeing. It is a classic wetland tree of European landscapes.
Materia Medica Summary
Black Alder / European Alder (Alnus glutinosa) is a wetland tree recorded in European folk medicine for astringent use of the dried bark on sore throats, mouth inflammation, and skin. Leaves have been applied as poultices. It is distinct from Alder Buckthorn. Fresh bark is emetic; dried material is used traditionally.