IngredientsThe plant known as cranesbill in herbal medicine is Geranium maculatum L., commonly called the wild geranium, spotted geranium, or wood geranium — a perennial plant native to woodlands in eastern North America, from southern Manitoba and southwestern Quebec south to Alabama and Georgia and west to Oklahoma and South Dakota. It belongs to the genus Geranium and the family Geraniaceae.
Its many common names include: American cranesbill, spotted cranesbill, spotted geranium, alumroot, alum bloom, wild geranium, storksbill, and chocolate flower. Additional colloquial names are alum root, alum bloom, and old maid's nightcap. In Europe, the plant is sometimes called spotted cranesbill or wild cranesbill, though the name "wood cranesbill" in a European context refers to the related G. sylvaticum, a different species.
The genus name Geranium comes from the Greek word geranos, meaning "crane," in reference to the fruit which purportedly resembles the head and beak of a crane. The specific epithet maculatum means "spotted." Geranium maculatum was named by Linnaeus in his monumental Species Plantarum, published in 1753.
It is a perennial herbaceous plant growing to 60 cm (2 ft) tall, producing upright, usually unbranched stems and flowers in spring to early summer. The leaves are palmately lobed with five or seven deeply cut lobes, 10–12.5 cm (4–5 in) broad, with a petiole up to 30 cm (12 in) long arising from the rootstock. Flowers are pink to lavender, rarely white, five-petaled, bowl-shaped, and grow in small terminal clusters on long stalks in the axils of stem leaves, blooming from April to June.
After flowering, distinctive beaked seed capsules form, giving rise to the common name "cranesbill." The root of Geranium maculatum is perennial, horizontal, thick, rough, and knobby. The plant is gynodioecious, with populations consisting of hermaphroditic individuals producing bisexual flowers and female individuals bearing pistillate flowers lacking functional stamens.
Wild geranium is a woodland perennial flower in the Geraniaceae family native to eastern North America. It is found naturally in base-rich, mesic forests. Its preference is for light shade to partial sunlight, moist to slightly dry conditions, and rich loamy soil with abundant organic matter. It is native to deciduous woodlands of eastern North America, from southern Ontario south to Georgia and west to eastern Oklahoma and the eastern part of the Dakotas, in hardiness zones 3 to 8.
American cranesbill is not the only species of the genus Geranium used in herbal medicine. The European species wood cranesbill (Geranium sylvaticum) and herb Robert (Geranium robertianum) are also used. Other pharmacologically investigated relatives include Geranium sanguineum (bloody cranesbill), used extensively in Bulgarian traditional medicine, and Geranium macrorrhizum (bigroot cranesbill). Since ancient times, species of the genus Geranium have been utilized in numerous conventional health systems across the globe, such as Indian Ayurveda, Traditional Chinese medicine, and various indigenous medical practices, by means of herbal formulations.
It is primarily the roots or the underground plant stems (rhizomes) of the plant that are used in herbal medicine, but sometimes the above-ground parts are used. Commercial preparations of the plant are usually derived from roots and/or rhizomes, and are available today as herbal or alternative medicines.
The plant is prepared and administered in several traditional forms:
G. maculatum was used medicinally by Native Americans to treat diarrhea and open sores or wounds. Thirty-two different uses by seven tribes have been documented. Some of these uses include making a decoction of roots for washing sores, boils, and itching; the root would be dried and pulverized for sores in the mouth. An infusion was taken for diarrhea or venereal disease.
The Blackfoot Indians of North America used the root of cranesbill and closely related plants to stop bleeding. Cranesbill has also been used by other indigenous tribes of North America to treat diarrhea. The Meskwaki people brewed a root tea for toothache and for painful nerves, and also mashed the roots for treating hemorrhoids. Members of the Chippewa tribe dried and pounded the rhizome to powder and applied it to lesions in the mouth, particularly in children. Other Native tribes steeped cranesbill in water and used the solution as eyewash. Powdered rhizome blended with other herbs and water was applied topically to wounds, and this blend was also used as a poultice to heal swollen feet.
Wild geranium has been used medicinally by Native Americans to treat diarrhea and various mouth ailments. Powdered preparations were used to treat open sores or wounds. Historically, geranium was also used in folk medicine to stop abnormal bleeding, including that related to menstruation and uterine problems. It may be applied topically to help treat hemorrhoids.
Early European settlers adopted similar uses, often as a remedy for gastrointestinal issues, sore throats, and mouth sores. When European settlers encountered the herb, they primarily used it to treat diarrhea, internal bleeding, cholera, and general diseases. It was also boiled with milk and cinnamon to treat dysentery.
The United States Dispensatory of 1926 noted, "Geranium is one of our best indigenous astringents." A manual published for physicians in the 19th century regarding cranesbill cites the extensive use of this plant, which possesses astringent attributes, for treating health conditions like hemorrhage, diarrhea, and dysentery. The handbook states that the herb was a well-accepted home remedy in several regions of North America. The rhizome of Geranium maculatum was also an official entry in the United States Pharmacopeia, reflecting its standing in formal 19th-century North American materia medica.
Traditional and folk uses documented across cultures and time periods include:
Geranium maculatum contains high levels of tannins, including hydrolyzable tannins such as geraniin, and gallic acid primarily in its rhizomes. These compounds confer astringent properties by contracting tissues and reducing secretions, as well as bacteriostatic effects that inhibit bacterial growth.
The major constituents of Geranium maculatum include tannin, gallic acid (after drying, from breakdown of the tannin), pectin, calcium oxide, gum, and resin. The root can contain between 12 to 25 percent tannin, with the highest amount just before flowering.
Since HPLC has found geraniin in each of the 15 species examined, geraniin appears to be the distinctive hydrolyzable tannin of the genus Geranium. Geraniin and its related molecule, ellagic acid, co-occur in Geranium plant leaves. The main sites for producing ellagic acid are the rhizomes and roots of the plants. Gallic acid, which is thought to be an ellagic acid precursor, has also been consistently seen in the roots and leaves. Gallic acid (a phenolic acid) has been specifically identified from the roots of G. maculatum.
Phytochemical investigations of Geranium species indicate the presence of phenolic compounds such as tannins, phenolic acids, and flavonoids. Ellagitannins are the most frequently isolated tannins, with geraniin being the principal one. In addition, proanthocyanidins have been reported. Phenolic acids are represented chiefly by gallic, ellagic, ferulic, caffeic, and chlorogenic acids. Flavonoids are abundant, including quercetin and kaempferol, as aglycones or in glycosidic combinations.
Cranesbill contains several active compounds, including tannins (particularly gallotannins and ellagitannins), which contribute to its astringent effect. Other components include flavonoids, resins, and small amounts of alkaloids, which may contribute to anti-inflammatory and antimicrobial effects.
The aerial parts of related Geranium species, notably G. robertianum, contain tannins (geraniin, isogeraniin, β-penta-O-galloylglucose), bitter substances, traces of essential oil, citric acid, resins, alkaloids, saponins, and oxalate. The main constituents of the essential oil isolated from aerial parts are represented by linalool, γ-terpinene, germacrene-D, limonene, geraniol, α-terpineol, and phytol. Several vitamins (A, B₁, B₂, B₃, C, and E) have been identified and quantified in leaves of related species.
The astringent action of cranesbill is largely due to its tannins, which help contract and tighten tissues. This property may help reduce inflammation, control minor bleeding, and support tissue repair. Spotted geranium contains chemicals called tannins. These have a drying effect and might be useful for conditions such as diarrhea.
Wild geranium is considered an astringent — a substance that causes contraction of the tissues and stops bleeding. Medicinal qualities can be attributed to the presence of gallic acid and tannins that provide astringent and bacteriostatic effects.
The tannin and gallic acid content confers bacteriostatic effects that inhibit bacterial growth. The high amount of tannins in both the herbal and root extracts should make an important contribution to the biological activities and the claimed indications in traditional medicine of Geranium species.
Species of the Geranium genus have significant pharmacological activities including anticancer, antioxidant, anti-inflammatory, and antimicrobial properties. Gallic acid, ellagic acid, and geraniin exhibit anticancer effects by inhibiting cell proliferation and triggering apoptosis in tumor cells, according to studies on various Geranium species.
Tannins in cranesbill may also reduce stomach acid by inactivating transporters (H⁺/K⁺-ATPase) involved in the production of hydrochloric acid. Cranesbill is high in tannins, which may account for its anti-diarrheal activity.
People use spotted geranium for skin wounds, diarrhea, other problems with digestion, and many other conditions, but there is no good scientific evidence to support these uses. Research on cranesbill is almost non-existent, but based on tannin research, cranesbill's traditional indications are considered pharmacologically plausible.
The anti-diarrheal rationale relies on general tannin pharmacology rather than clinical trials specifically conducted with G. maculatum. Little scientific research exists to clarify cranesbill's constituents and actions specifically. Dried, powdered cranesbill root is sometimes used in an herbal combination to treat Crohn's disease; however, there are no scientific studies to support this combination.
Evidence strength: Traditional and mechanistically plausible, but not supported by published controlled human clinical trials specific to G. maculatum. The evidence is entirely pre-clinical and ethnobotanical at this time.
While formal clinical trials on cranesbill's effects are limited, some preliminary studies and anecdotal evidence suggest efficacy in managing mild gastrointestinal complaints, inflammation, and minor bleeding. The astringent and styptic properties attributed to cranesbill are consistent with the known actions of hydrolyzable tannins on tissue proteins, causing precipitation of proteins at the surface of wounds and mucous membranes. Scientific investigations support the traditional use of wild geranium for its astringent and hemostatic effects. These properties are essential for wound healing and controlling bleeding. However, as with gastrointestinal uses, these findings are based on pre-clinical rationale rather than conducted clinical trials.
Evidence strength: Mechanistically plausible; no controlled human clinical trial data currently available specific to this species.
Modern scientific studies have proved antimicrobial and antiviral effects of G. sanguineum extracts in vitro. The plant and root extracts of Geranium sanguineum have been used in folk medicine for a long time as a remedy for the treatment of diarrhoea and wounds. Studies have confirmed the antibacterial activity (against a very limited panel of bacteria), as well as antioxidant, anti-inflammatory, and antihyperglycemic activities in the genus.
For G. maculatum specifically, the ethanolic extract of G. maculatum was found to be cytotoxic to the Neuro 2-a murine neuroblastoma cell line, with an LC₅₀ value of 1.170 mg/ml, in studies by Mazzio and Soliman (2009). The Geranium maculatum ethanolic extract was reported to possess moderate inhibitory growth (IG₅₀ 60.2 µg/mL) against MDA-MB-231 (human breast cancer) cells. These are in vitro findings only.
For antiviral effects in the broader genus: one study demonstrated antiviral effects of a Geranium species and its constituent hyperin against hepatitis B virus (Li et al., 2008, in Biological and Pharmaceutical Bulletin). A spray containing Geranium sanguineum protected mice from influenza in an animal model (Serkedjieva et al., 2008, in Die Pharmazie). These findings were in related species, not G. maculatum itself.
Evidence strength: In vitro and animal data only. No human clinical trials for antimicrobial or antiviral effects of G. maculatum have been identified in the current literature.
Based on the high content of polyphenols and pronounced antioxidant and antimicrobial activities observed in Geranium species, examined extracts are considered promising natural antioxidant and antimicrobial agents with potential medicinal purpose. The Geranium genus has been studied for a wide range of pharmacological properties including antioxidant, antiproliferative, cytotoxic, anti-inflammatory, anti-ulcerative, analgesic, antidiabetic, immunomodulatory, antibacterial, antifungal, and antiviral activities. However, these findings pertain to the genus broadly, and species-specific data for G. maculatum remain limited.
Evidence strength: In vitro and genus-level evidence. Translatable human relevance has not been established in clinical trials.
People have taken spotted geranium for canker sores and gum disease, and it is sometimes applied to the affected area for skin wounds, bleeding sores, hemorrhoids, vaginal discharge, and a fungal infection called thrush. These applications derive from the astringent and bacteriostatic properties of tannins, supported by traditional use records rather than clinical trials.
Evidence strength: Ethnobotanical and mechanistically rationale only; no clinical trial data.
Historically, geranium was used in folk medicine to stop abnormal bleeding, including that related to menstruation and uterine problems. Cranesbill is used to stop abnormal bleeding related to menstruation and uterine problems. These are traditional claims not validated by controlled clinical studies.
Evidence strength: Traditional use record only; no clinical evidence.
Based on traditional use and pre-clinical pharmacology, cranesbill has been associated with the following body systems and conditions:
The following dosages are those reported in herbal reference sources and traditional practice guides, not from controlled clinical trials, as no such trials for G. maculatum have been identified:
The appropriate dose of spotted geranium depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate standardized dose.
Geranium maculatum is generally considered safe and has a long history of ethnobotanical use. Cranesbill tea should not be used for more than two to three consecutive weeks. Due to the high tannin content, some people may develop an upset stomach after using cranesbill.
Geranium maculatum is generally considered safe for use in moderate amounts. However, its astringent properties mean that overuse can lead to constipation or gastrointestinal discomfort. For short-term internal use only, due to the high amount of tannins.
Cranesbill is considered a safe herb; however, it should be used with caution in people with spastic, dry constipation or people taking anticholinergic medication, as it will potentiate smooth muscle irritability.
At the time of available reporting, there were no well-known supplement or food interactions with cranesbill. No reported interactions between this supplement and medicines had been found. Because tannins can bind to and reduce the absorption of certain minerals and drugs taken concurrently, this is a theoretical concern relevant to any high-tannin herb, though it has not been specifically documented for G. maculatum in the clinical literature reviewed.
Cranesbill tea should not be used for more than two to three consecutive weeks. No long-term safety data from controlled studies in humans have been identified for this plant.
Little scientific research exists to clarify cranesbill's constituents and actions specifically for Geranium maculatum. Formal clinical trials on cranesbill's effects are limited; some preliminary studies and anecdotal evidence suggest efficacy in managing mild gastrointestinal complaints, inflammation, and minor bleeding, but more rigorous trials are needed to confirm these effects and establish dosing parameters. Most pharmacological data originate from related species — especially G. sanguineum, G. robertianum, and G. macrorrhizum — and cannot be automatically extrapolated to G. maculatum without species-specific research. The Geranium genus is chemically rich, but species-specific profiling is still uneven. Wild geranium clearly belongs to this tannin-heavy, polyphenol-rich group, yet its folk reputation was built more on observable action than on exhaustive modern standardization.
Health conditions that Cranesbill may help support.
Body systems that Cranesbill may help support.
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