Herbal Medicine - Alder
Herbal Medicine – Alder
Botanical Information
Alder (Alnus glutinosa), commonly known as Black Alder, along with related species such as Alnus rubra (Red Alder), belongs to the Betulaceae family. It is a medium-sized deciduous tree that can grow up to 30 metres tall. Alder is recognized by its smooth grey bark, rounded serrated leaves, drooping catkins that appear in early spring, and small woody cone-like fruits known as strobiles.
Habitat and Cultivation
Alder is native to Europe, North America, and parts of Asia, where it naturally grows along riverbanks, wetlands, and other damp environments. It thrives in moist, well-drained soils and forms a beneficial relationship with nitrogen-fixing bacteria in its roots, helping to improve soil fertility. Because of this ability, alder is widely used in reforestation, land restoration, and erosion control projects.
Parts Used
The primary medicinal parts include the bark, leaves, and catkins.
Active Compounds
Alder contains several bioactive compounds, including tannins, flavonoids, triterpenes, diarylheptanoids, phenolic acids, and small amounts of essential oils. These compounds contribute to its antioxidant, anti-inflammatory, antimicrobial, and astringent properties.
Traditional Uses
Alder has a long history of medicinal use in many cultures. In European folk medicine, bark decoctions were traditionally used to reduce fever, soothe sore throats, and relieve inflammatory skin conditions. Native American tribes used Red Alder bark as a blood purifier and to ease rheumatism, headaches, and muscular pain, while fresh leaves were applied as poultices to burns, wounds, and swellings. In Siberian traditional medicine, bark infusions were commonly taken to relieve diarrhoea, dysentery, and other digestive complaints.
Evidence-Based Health Benefits
Modern studies suggest that alder possesses significant anti-inflammatory activity, supporting its traditional use for arthritis and inflammatory skin conditions. Laboratory research has also demonstrated antibacterial and antifungal effects, while its rich polyphenol content provides strong antioxidant protection that may benefit cardiovascular and liver health. The high tannin content contributes to its traditional use as an astringent for supporting digestive health and managing diarrhoea.
Common Preparations
Alder bark is commonly prepared as a decoction, which may be used as a gargle for sore throats or as a skin wash for minor irritations. Alcohol-based tinctures of the bark are traditionally taken in small amounts for internal use. Fresh leaf poultices have long been applied to burns, ulcers, wounds, and swollen joints. Powdered bark is also occasionally available in capsules or herbal supplements designed to support digestive health.
Safety and Precautions
Alder is generally considered safe when used externally or in traditional moderate doses. However, excessive internal use of the bark may cause nausea, stomach irritation, or digestive discomfort because of its high tannin content. Pregnant and breastfeeding women should avoid medicinal use unless advised by a qualified healthcare professional.
Cultural Significance
In Celtic tradition, alder was regarded as a sacred tree symbolizing strength, protection, and guidance. Its durable wood, which becomes stronger when submerged in water, was widely used to build bridges, pilings, shields, and other structures. Folklore described alder trees as guardians of rivers and wetlands, and carrying alder bark was believed to offer protection, courage, and resilience.
Current Research
Current scientific research focuses on diarylheptanoids isolated from alder bark, which have demonstrated promising anti-inflammatory, antioxidant, and potential anticancer properties in laboratory studies. Researchers continue to investigate Red Alder for its ability to reduce chronic inflammation and oxidative stress, with the goal of developing future therapeutic applications.
