Taxonomic Class

Betulaceae

Common Trade Names

None known.

Common Forms

Available as dried bark, essential oil (bark, wood), and tea. Source

Active compounds of birch are derived from the dried bark and twigs of the birch species Betula alba (Betula pendula), Betula verrucosa, Betula pubescens, and Betula lenta. Several birch species are native to eastern North America, Europe, and parts of Russia.

Chemical Components

Distillation of the bark of B. alba yields betulin, birch tar oil, creosol, cresol, guaiacol, isomeric hydrocarbons, phenol, pyrocatechol, turpentine oil, and xylenol. Avicularin, flavonoids, galactosyl-3 myricetol, glucuronyl-3 quercetol, hyperoside, and quercetin occur in the dried leaves. Sweet birch oil is produced by steam distillation of the watersoftened bark of B. lenta. Methyl salicylate is liberated in the process. Sweet birch oil is composed almost entirely of methyl salicylate.

Actions

Methyl salicylate has analgesic, anti-inflammatory, and antipyretic properties. Hemostatic function in animals is affected by the thromboplastic agents presumably found in B. pendula. The mechanism of action resembles that of human tissue thromboplastin. In other animal studies, birch has been shown to exert diuretic properties .

Reported Uses

Claims for birch include relief of headaches and other analgesic effects as well as treatment of various acute and chronic skin disorders, GI disorders, and kidney stones. Essential oils are claimed to act against bladder infections, gout, neuralgias, rheumatism, and tuberculous cervical lymphadenitis. In veterinary medicine, essential oil of birch wood has been used to treat various skin diseases.

Dosage

Extracts or teas can be made by steeping 2 to 3 g of the bark in boiling water for 10 to 15 minutes; the infusion may be ingested several times daily.

Adverse Reactions

Skin : acute contact dermatitis.

Eent : allergic rhinitis.

Other : cross-sensitization with other plant allergens, such as celery and mugwort pollen .

Interactions

None reported.

Contraindications And Precautions

Birch is contraindicated in pregnant or breast-feeding patients. Use cautiously in patients with seasonal allergic rhinitis or hypersensitivity to plant allergens.

Special Considerations

Monitor for signs and symptoms of allergic reaction, particularly in patients with allergies to celery, mugwort, or other plants.

Alert Caution the patient to keep birch preparations out of the reach of children. Sweet birch oil is composed of 98% methyl salicylate, which can be fatal to children when applied topically to the skin. Poisonings have been reported with as little as 4.7 g of methyl salicylate applied topically.

Advise the patient that topical preparations may irritate the skin and mucous membranes. Encourage him to report new or unusual dermatologic manifestations.

Advise women to avoid using birch products during pregnancy or when breast-feeding.

Points of Interest

Betulin is being evaluated for its antitumorigenic properties.

In Germany, leaves of B. pendula are used as a diuretic during irrigation therapy for urinary tract infections.

Commentary

Chemical compositions from birch possess some interesting properties. However, until more clinical research becomes available, these agents have no role in modern medicine. The risk of hypersensitivity reactions makes OTC use a cause for concern.