Plant Monograph: American Cranesbill

Name of plant:
American cranesbill

Traditional Lore

American cranesbill, a native North American wild geranium, has been valued in traditional herbal practice for generations. Indigenous peoples and later herbalists recognized the usefulness of its deeply astringent root, which earned it a place among the dependable remedies of the woodland pharmacopeia. Growing in meadows, forest edges, and shaded clearings, the plant was gathered seasonally and prepared as part of household medicine traditions. Through its long history of use, American cranesbill came to symbolize balance, restraint, and the restorative qualities of the forest landscape.

Family:
Geraniaceae

Genus and species:
Geranium maculatum

Other names:
Wild geranium, Spotted geranium, Alum root (shared folk name), Cranesbill geranium

Brief introduction:
American cranesbill is a perennial woodland herb native to eastern North America. It is recognized by its deeply lobed leaves and delicate pink-purple flowers. The plant is most valued medicinally for its astringent root, which has been widely used in traditional North American herbalism for gastrointestinal and mucosal support.

Traditional uses:

• Diarrhea and gastrointestinal irritation (astringent remedy)

• Mouth and throat rinses for inflammation

• Topical washes for minor wounds and skin irritation

• Hemorrhoidal support in traditional herbal practice

• General mucosal toning in folk herbal systems

Historical use:

• Used by Indigenous North American peoples for digestive and wound care

• Adopted into 19th-century Eclectic and Physiomedical herbalism

• Frequently included in North American materia medica as a reliable astringent root

• Used in household herbal medicine as a substitute for imported astringents like imported tannin-rich barks

• Continued use in Western herbalism into the present as a mild, safe astringent

Parts used and method of use:

• Root (primary medicinal part)

• Occasionally aerial parts, but much weaker in effect
  Used as:

• Decoction (root tea)

• Tincture

• Powdered root in capsules (modern herbal practice)

• Topical wash or compress

Use in healing (modern herbal practice):

• Strong astringent for gastrointestinal irritation and mild diarrhea

• Mucosal toning herb for mouth, throat, and gut lining

• Topical support for minor wounds and skin irritation

• Hemorrhoidal comfort applications (traditional use)

• Considered a reliable but gentle tannin-based herb in Western herbalism

Pharmacology and biochemistry:

• High levels of tannins (gallotannins and related polyphenols)

• Contains flavonoids and phenolic acids

• Mechanism:

  • Protein precipitation → reduced secretions and tissue tightening

  • Mild antimicrobial activity via tannin action

• Observed effects:

  • Astringent action on mucous membranes

  • Reduction of intestinal fluid secretion (supporting anti-diarrheal use)

  • Mild anti-inflammatory activity in topical use

Common dosage:

• Decoction: 1–2 teaspoons dried root per cup, simmered 10–15 minutes, up to 2–3 times daily

• Tincture (1:5 or similar): 2–4 mL up to 3 times daily in traditional herbal practice

• Powdered root: 0.5–2 g per dose (less commonly used internally today)

Safety factors (including side effects):

• Generally safe in traditional doses

• High tannin content may cause constipation if overused

• May irritate stomach in sensitive individuals if taken in excess

• Not recommended for long-term continuous use without breaks

• Very low toxicity profile compared to stronger astringents

First aid / adverse reaction response:

• Constipation: reduce dose or discontinue use

• GI irritation: stop use and hydrate

• Rare allergic reaction: discontinue and seek medical advice if severe

• No known acute toxicity at traditional dosing levels

Drug interactions:

• May reduce absorption of oral medications if taken simultaneously (tannin binding) → separate dosing by 1–2 hours

• No well-documented clinically significant drug interactions

• Caution with iron supplements if taken at same time (reduced absorption possible)

Horticultural requirements:

• USDA / Canadian zone: 3–8

• Soil pH: 5.5–7.0 (prefers slightly acidic woodland soils)

• Light requirements: Partial shade to full shade

• Moisture: Moderate; prefers moist, well-drained woodland soils

• Other notes (growth habit, harvest timing, etc.):

  • Woodland perennial, 30–60 cm tall

  • Flowers in late spring to early summer

  • Roots harvested in autumn of second year or later for highest potency

  • Spreads slowly in suitable forest-floor conditions

  • Often found in deciduous forest understories

Sampling of clinical reports / studies:

• Phytochemical studies confirm high tannin content as primary active constituent

• In vitro research shows mild antimicrobial and antioxidant activity from polyphenolic compounds

• Historical Eclectic medicine literature consistently documents use as a dependable anti-diarrheal and mucosal astringent

• Limited modern clinical trials exist; most evidence is based on traditional use and phytochemical inference

• Contemporary herbal consensus classifies it as a safe, moderate-strength astringent herb for gastrointestinal and mucosal support

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• ​Educational Use Only: The information presented on this page is provided for educational, historical, and informational purposes only. ArdNemeton na Tuatha and Bhùth Draoi do not provide medical advice. Always consult your physician and pharmacist before using any herb, mushroom, supplement, or botanical product for medicinal purposes. Traditional uses described herein do not constitute medical claims.