Mountain Bluebells (Mertensia ciliata): A Comprehensive Reference
1. Identity and Botanical Classification
Scientific Nomenclature and Taxonomy
Mertensia ciliata is a species of flowering plant in the borage family (Boraginaceae), known by the common names mountain bluebell, tall fringed bluebells, and streamside bluebells. Its formal scientific name is Mertensia ciliata (James ex Torr.) G. Don, reflecting that the species was first described from specimens collected by Edwin James and later formally circumscribed by George Don. The genus Mertensia belongs to the family Boraginaceae — the same family that includes comfrey (Symphytum officinale), borage (Borago officinalis), and the Virginia bluebell (Mertensia virginica).
Mertensias are also called Lungworts, after a European species with spotted leaves which was believed to be a remedy for lung disease. Similar species differ in the proportions of the corolla. This folk name reflects an older taxonomic relationship: the Mertensia genus was once considered a species of Pulmonaria (aka Lungworts), which were used generally as remedies for diseased lungs on account of their tendencies to have white-spotted leaves.
Mertensia virginica is the type species for the genus Mertensia and was first described by Linnaeus in 1753 as Pulmonaria virginica. The genus was subsequently separated from Pulmonaria and named in honour of the German botanist Franz Karl Mertens.
Morphological Description
Mertensia ciliata is a perennial herb producing a cluster of erect stems from a thick, branching caudex. The leafy stems reach well over a meter in maximum height. The leaves are up to 15 centimetres (6 in) long, veiny, and oval to lance-shaped. Mountain bluebells leaves are blue-green in colour and have distinct lateral veins. The basal leaves, when present, are elliptic or oval in shape (generally not heart-shaped) and long stalked. Stem leaves are alternate and become slightly smaller as you move upward along the stem. The stem leaves are lance-shaped.
Blooming from May to August, the inflorescence is an open array of many clustered blue bell-shaped flowers each between 1 and 2 cm (½ and ¾ in) long. The hanging, fragrant flower is tubular, expanding into a wider, lobed mouth. As the individual flowers progress in age they change in colour from blue to pink-red. Fruits/Seeds are nutlets, in fours, dark brown or black when mature.
Geographic Range and Natural Habitat
It is native to the western United States, in California, Nevada, Utah, and Oregon. It often grows in moist habitat, such as subalpine meadows and creeksides. Its native distribution spans Colorado and extreme northern New Mexico to the California Sierras, and north into the western mountain states. Native habitat includes stream banks, wet meadows, and damp thickets.
Common Forms and Preparations
The flowers of mountain bluebells are edible raw. The leaves are edible raw or cooked. The plant is galactogogue, and a tea of the plant was used by the Cheyenne Indians to increase the milk flow of nursing mothers.
The plant appears in traditional and folk use primarily in three preparation forms: (1) infusions or teas brewed from leaves and flowers; (2) decoctions made from the powdered root; and (3) external poultices made from crushed or prepared leaves. Traditionally, the fresh or dried leaves and flowers were brewed into teas or poultices thought to aid in respiratory discomfort, soothe minor wounds, and support general wellness. In the contemporary supplement market, mountain bluebell may appear as a dried herb ingredient in multi-botanical blends, though no standardized extract, capsule dosage form, or monograph-regulated preparation has been established for this species by any major pharmacopeial authority.
2. Traditional and Historical Use
Native American Ethnobotany
Mountain Bluebells (Mertensia ciliata), also known as Tall Bluebells or River Bluebells, have a rich history of medicinal use among indigenous peoples and early settlers in North America. Traditionally, Native American groups such as the Navajo and Ute recognized the gentle, soothing properties of Mountain Bluebells and utilized its leaves and blossoms in a variety of natural remedies.
Among the Cheyenne, two distinct uses are documented. A tea of the plant was used by the Cheyenne Indians to increase the milk flow of nursing mothers. Additionally, the Cheyenne Native Americans made a tea of the powdered root and used it to relieve the itching caused by smallpox and measles. An ethnobotanical study of Cheyenne plant knowledge further documents that Mertensia ciliata was mixed with sweet medicine or bitter medicine (Oxytropis) to increase milk flow.
Infusions made from the plant were commonly used to ease respiratory issues, such as coughs and sore throats. In addition, poultices prepared from the leaves were sometimes applied topically to promote the healing of minor wounds, burns, and skin irritations.
The Broader Mertensia Genus in Traditional Medicine
The traditional medical uses of the genus Mertensia extend across multiple species and cultures. Several Mertensia species are traditionally used to treat tuberculosis, venereal diseases, and whooping cough. The closely related Virginia bluebell (Mertensia virginica), for example, was employed by multiple Eastern Woodlands tribes: Virginia bluebells had several uses in traditional Native American medicine, including as a pulmonary aid, tuberculosis treatment, and treatment for whooping cough (Cherokee), root infusion antidote for treating poison, and root decoction to treat venereal issues (Iroquois).
Across Siberian and Central Asian traditions, related species in the genus have served comparable roles. Two North bluebells, Mertensia stylosa and M. serrulata, are plants used in the traditional medicine of the Buryats as wound healing and antitumor remedies. Both mertensias have been used by local healers as substitutes for the rare Tibetan raw material Cynoglossum amabile.
Food and Dye Uses
Beyond medicine, mountain bluebell has a documented history as a wild food. The flowers and leaves are edible. The flowers have been used as a natural dye. The edibility of both plant parts places M. ciliata among the forager's repertoire of western North American wild plants, with the mild flavour characteristic of the Boraginaceae family.
3. Key Chemical Constituents
Pyrrolizidine Alkaloids
The most pharmacologically and toxicologically significant chemical class found in Mertensia ciliata is the pyrrolizidine alkaloids (PAs). Pyrrolizidine alkaloids such as lycopsamine and intermedine were found in M. ciliata (James) G. Don. This finding is further corroborated by multiple analytical studies: for M. ciliata, intermedine and lycopsamine have been identified.
Previously, lycopsamine and lycopsamine N-oxide have been identified in M. bakeri, M. ciliata, and M. maritima. Acetate derivatives of lycopsamine and lycopsamine N-oxide were revealed in the Mertensia genus.
Research on closely related bluebells gives an indication of the alkaloid profile complexity across the genus. In a study of Mertensia stylosa and M. serrulata, LC-MS/MS metabolite profiling resulted in the identification of 30 compounds, including hydroxycinnamates, flavonoids, and pyrrolizidine alkaloids. Lycopsamine N-oxide was the dominant alkaloid in M. stylosa (5.27 mg/g) and M. serrulata (2.14 mg/g) herbs. The derivatives of lycopsamine found in the studied species of the Mertensia herb include lycopsamine N-oxide, lycopsamine 7-O-acetate and its isomer, and lycopsamine N-oxide 7-O-acetate and its isomer.
At the family level, according to chemotaxonomic data on the distribution of alkaloids in the Boraginaceae family, the species of genus Mertensia produce alkaloids of the retronecine type.
Phenolic Compounds and Flavonoids
Research on the Mertensia genus documents a range of phenolic secondary metabolites alongside the alkaloid fraction. Four flavonoid compounds were identified in the herbs of both Mertensia species studied; the found flavonoids belonged to the flavonol group depending on their aglycone structures and were derivatives of quercetin. Quercetin-3-O-glucoside and kaempferol-3-O-rutinoside have been detected in shoots of M. maritima.
In studies of closely related North bluebell species, 5-O-caffeoylquinic acid (43.41 mg/g) and rutin (42.40 mg/g) prevailed among the phenolic compounds in M. stylosa herb, while rutin (25.72 mg/g) was the dominant compound of the M. serrulata herb. These hydroxycinnamic acid derivatives (such as caffeoylquinic acid) and flavonols (such as rutin and quercetin derivatives) are consistent with the broader phytochemical profile of the Boraginaceae family.
Other Bioactive Metabolites
Studies of Mertensia maritima, a closely related species, have identified a broader phytochemical inventory. Pyrrolizidine alkaloids are one of the main bioactive compounds of Boraginaceae members. For the first time, seven pyrrolizidine alkaloids, such as echimidine, heliosupine, heliotrine, intermedine or lycopsamine, and their N-oxides were identified in M. maritima extracts by UHPLC-MS/MS. Carotenoids, tocopherols, and fatty acids including alpha-linolenic acid have also been detected in Mertensia tissue cultures, though these analyses pertain primarily to M. maritima rather than to M. ciliata specifically.
4. Mechanisms of Action
Galactogogue Activity
The best-documented traditional use — increasing milk production in nursing mothers — assigns a galactogogue function to the plant. The plant is galactogogue, and a tea of the plant was used by the Cheyenne Indians to increase the milk flow of nursing mothers. The phytochemical mechanism underlying this effect in M. ciliata specifically has not been characterised in peer-reviewed pharmacological literature. The attribution of galactogogue activity likely reflects centuries of empirical indigenous observation rather than a mechanistically elucidated biological pathway.
Pyrrolizidine Alkaloid Mechanisms
The pyrrolizidine alkaloids documented in M. ciliata — primarily intermedine and lycopsamine — are well-characterised in terms of their general toxicological mechanism. PAs exert hepatotoxicity via cytochrome P450-mediated metabolic activation, forming pyrrole-protein adducts which impair the biological activities of some functional proteins, resulting in liver damage. PA-induced liver injury was initiated by cytochrome P450 (CYP)-mediated metabolic activation and subsequent formation of adducts with cellular proteins.
When the liver was exposed to PAs, liver sinusoidal endothelial cells (LSECs) loss, haemorrhage, liver parenchymal cells death, nodular regeneration, Kupffer cells activation, and fibrogenesis occurred. These pathological changes classified the PAs-induced liver injury as acute, sub-acute, and chronic type. PA metabolic activation, mitochondria injury, glutathione (GSH) depletion, inflammation, and LSECs damage-induced activation of the coagulation system were well recognised to play critical roles in the pathological process of PAs-induced hepatotoxicity.
Phenolic / Flavonoid Antioxidant Mechanisms
The flavonoids (quercetin derivatives, rutin, kaempferol glycosides) and hydroxycinnamic acids (caffeoylquinic acid) identified across the Mertensia genus belong to compound classes with well-characterised general antioxidant and anti-inflammatory mechanisms in the broader scientific literature. Studies of related bluebell species have demonstrated radical-scavenging capacity. The investigated extracts of M. stylosa and M. serrulata herb revealed good scavenging capacity against DPPH•, ABTS•+, and DMPD•+ radicals. Whether these in-vitro antioxidant properties translate to clinically relevant effects in humans when consuming preparations of M. ciliata specifically has not been tested.
5. Scientific Evidence by Area of Use
Overview of the Evidence Landscape
It is essential to state at the outset that, as of the date of this article, no published human clinical trials, randomised controlled trials, or systematic reviews have evaluated preparations of Mertensia ciliata as a dietary supplement or herbal medicine in human subjects. All documented "evidence" for the plant's medicinal applications is derived from: (1) historical and ethnobotanical records of traditional use; and (2) in-vitro or phytochemical studies, some of which concern related but distinct Mertensia species rather than M. ciliata itself. Claims made about this plant in dietary supplement contexts are therefore not substantiated by clinical evidence and should be regarded as unverified.
Galactogogue (Milk Production)
Traditional evidence: The plant is galactogogue, and a tea of the plant was used by the Cheyenne Indians to increase the milk flow of nursing mothers.
Scientific evidence: No human clinical studies, animal studies, or in-vitro mechanistic studies specifically evaluating the galactogogue effect of M. ciliata have been identified in the peer-reviewed literature. The traditional attribution of this property cannot be evaluated for efficacy or safety in lactating individuals on the basis of available scientific data.
Respiratory Support (Coughs, Sore Throats)
Traditional evidence: Infusions made from the plant were commonly used to ease respiratory issues, such as coughs and sore throats, thanks to its mild expectorant qualities. This use is broadly consistent with the traditional applications documented for the genus: several Mertensia species are traditionally used to treat tuberculosis, venereal diseases, and whooping cough.
Scientific evidence: No human clinical studies or controlled pharmacological studies specific to M. ciliata for respiratory outcomes have been identified. The genus name "Lungwort," derived from the historical classification within Pulmonaria, reflected the Doctrine of Signatures rather than documented efficacy. Evidence for respiratory effects remains at the level of traditional documentation only and is not supported by clinical data.
Wound Healing and Skin Applications
Traditional evidence: Poultices prepared from the leaves were sometimes applied topically to promote the healing of minor wounds, burns, and skin irritations. Related bluebells share this use: M. stylosa and M. serrulata are plants used in the traditional medicine of the Buryats as wound healing and antitumor remedies.
Scientific evidence: No controlled studies of topical M. ciliata preparations for wound healing have been published. The plant's noted similarity to comfrey (also in Boraginaceae, which contains allantoin associated with wound-healing properties) is an informal folk observation without verified phytochemical documentation specific to M. ciliata.
Anti-inflammatory and Antioxidant Effects
In-vitro evidence (related species): The investigated extracts of M. stylosa and M. serrulata herb revealed good scavenging capacity against DPPH•, ABTS•+, and DMPD•+ radicals. This finding pertains specifically to two Siberian/Buryat bluebell species, not M. ciliata. Whether comparable scavenging capacity exists in M. ciliata extracts has not been independently documented in the peer-reviewed literature.
Human/clinical evidence: None identified. Evidence is limited to in-vitro radical scavenging assays in taxonomically related species, which represents a very early and preliminary stage of evidence; such data cannot be extrapolated to confirm therapeutic benefit in humans.
Itching Associated with Infectious Disease (Smallpox, Measles)
Traditional evidence: The Cheyenne Native Americans made a tea of the powdered root and used it to relieve the itching caused by smallpox and measles. This use is documented exclusively within Cheyenne ethnobotanical records and reflects a pre-vaccination historical context.
Scientific evidence: None. This application has no corroborating pharmacological or clinical evidence and refers to conditions (smallpox) that are no longer clinically relevant in public health contexts.
6. Body Systems and Health Areas Associated with Mountain Bluebells
- Reproductive system / Lactation: Galactogogue use by Cheyenne people, traditionally prepared as a tea.
- Respiratory system: Traditional use for coughs, sore throats, and related conditions across multiple Native American traditions and within the broader Mertensia genus tradition.
- Integumentary system (skin): Topical poultice use for wounds, burns, and skin irritations.
- Immune / Infectious disease: Historical use for symptom relief associated with smallpox and measles.
- Hepatic system (risk, not benefit): Due to the presence of pyrrolizidine alkaloids, the liver is the primary organ at risk from improper or prolonged use (see Safety section).
No body system association has been confirmed by clinical evidence. All associations listed above are derived from traditional ethnobotanical records.
7. Dosage Forms and Reported Dosages
No standardised dosage has been established for Mertensia ciliata by any regulatory body, pharmacopeia, or institutional health authority. No clinical trials have tested specific dosages in human populations. The following preparations are mentioned exclusively in ethnobotanical and descriptive sources:
- Herbal tea / infusion: Fresh or dried leaves and flowers brewed in water. No gram weight, steeping time, or cup volume has been specified in authoritative sources reviewed.
- Root decoction / powdered root tea: The Cheyenne Native Americans made a tea of the powdered root for topical symptom relief. No quantitative dosage parameters are documented in available sources.
- Topical poultice: Leaves prepared as a poultice and applied externally. No standardised preparation instructions have been documented in the peer-reviewed literature.
- Raw consumption (food): The flowers of mountain bluebells are edible raw. The leaves are edible raw or cooked.
The absence of any clinical dosage data means that no safe or effective dose range can be stated for this plant as a supplement. Quantities consumed in the context of wild food are undefined and varied.
8. Safety Considerations and Known Interactions
Pyrrolizidine Alkaloid Hepatotoxicity
The most significant safety concern for Mertensia ciliata relates directly to its documented alkaloid content. Pyrrolizidine alkaloids such as lycopsamine and intermedine were found in M. ciliata. These compounds are members of the retronecine-type PA class, and their toxicological significance is well established.
1,2-unsaturated PAs have been associated with adverse consequences such as hepatotoxicity, nephrotoxicity, genotoxicity, mutagenicity, and carcinogenesis.
Herbal remedies containing pyrrolizidine alkaloids (PAs) can induce liver damage, including hepato-sinusoidal obstruction syndrome (HSOS) or veno-occlusive liver disease (VOD). The consumption of herbal medicines and herbal teas containing PAs is one of the main causes of hepatic sinusoidal obstruction syndrome (HSOS), a potentially life-threatening condition.
HSOS is clinically characterised by hepatic congestion and swelling, blockage of liver blood vessels, detachment of sinusoidal endothelial cells and hepatic dysfunction. Through an in-depth study of these HSOS patients, it was found that most of them were exposed to pyrrolizidine alkaloids (PAs) through the consumption of herbals and herbal teas.
A specific PMC study on the hepatotoxicity of intermedine — one of the two PAs identified in M. ciliata — evaluated its cytotoxicity in primary mouse hepatocytes, human hepatocytes, and hepatocellular carcinoma cell lines, confirming its classification as a hepatotoxic compound consistent with other retronecine-type PAs.
Regulatory Context for Pyrrolizidine Alkaloids in Herbal Products
Pyrrolizidine alkaloids (PAs) are distributed in plant families of Asteraceae, Boraginaceae, and Fabaceae and serve in the chemical defence mechanism against herbivores. They became a matter of concern due to their toxicity associated with the high risk of intake within herbal preparations, such as phytopharmaceutical formulations, medicinal teas, or other plant-derived drug products. In 1992, the German Federal Ministry of Health established the first limits of PA content for fourteen medicinal plants.
The European Medicines Agency (EMA) issued a public statement in 2016 (EMA/HMPC/328782/2016) on contamination of herbal medicinal products with pyrrolizidine alkaloids, and the European Union subsequently set maximum levels for PA content in certain foodstuffs including borage leaves from the same plant family. While these regulations address closely related Boraginaceae members, they reflect the broader regulatory concern relevant to M. ciliata and its PA content.
Dose-Dependent Toxicity
Pyrrolizidine alkaloids are known to have hepatotoxic and potentially carcinogenic properties. The dose-dependence of PA-induced liver injury is documented: the biological and histological results showed dose-dependent hepatotoxicity with significantly different toxic severity among groups. Both serum ALT activity and the amount of hepatic pyrrole-protein adducts increased in a dose-dependent manner.
Genotoxicity and Carcinogenicity
PA which exhibit a 1,2-unsaturated structure are liver toxic and bear a genotoxic potential after their metabolic activation. Both lycopsamine and intermedine, the specific PAs identified in M. ciliata, belong to the retronecine type and may have unsaturated necine base structures associated with this concern.
Absence of Data in Special Populations
No safety data are available for the use of M. ciliata preparations in pregnancy, breastfeeding women (despite the traditional galactogogue application), children, or individuals with pre-existing hepatic conditions. Given the known hepatotoxicity of PAs at sufficient doses, and the absence of any established safe dose, use in lactating women is particularly notable because PA exposure could theoretically transfer to the nursing infant — a concern that has been identified for PA-containing plants in the Boraginaceae family more broadly.
Interactions
No drug-herb interaction studies have been conducted for M. ciliata preparations. As PAs are metabolically activated by cytochrome P450 enzymes (particularly CYP3A4 and related isoforms), co-administration of M. ciliata preparations with drugs or substances that inhibit or induce CYP450 pathways would theoretically alter PA toxicity. PA-induced liver injury was initiated by cytochrome P450 (CYP)-mediated metabolic activation. This represents a theoretical interaction pathway, not one documented in controlled studies of M. ciliata specifically.
Wild Foraging Considerations
When consumed as a wild food in modest quantities, mountain bluebells are traditionally regarded as safe. There is no poisonous look-alike, and the plant is considered easily identifiable in its native habitat. However, foragers should be aware that the same plant that is safe as an occasional food item may carry different risk implications when consumed in concentrated supplemental preparations, particularly over extended periods, due to PA accumulation.
9. Status in Contemporary Dietary Supplement Use
Mountain bluebell (M. ciliata) occupies a limited niche in the dietary supplement marketplace. It appears as an ingredient in some multi-herb products. In the realm of modern herbal nutrition, Mountain Bluebells continue to contribute as a valued ingredient, supporting holistic approaches to health. Its inclusion in contemporary nutritional products reflects both its historical legacy and its ongoing reputation as a botanical. However, no product containing M. ciliata has received review or approval from the U.S. Food and Drug Administration (FDA), the European Medicines Agency (EMA), or any comparable regulatory body for any health claim or therapeutic use. The plant is absent from Commission E monographs, ESCOP monographs, WHO herbal monographs, and the European Pharmacopoeia. It is not listed in the NIH Office of Dietary Supplements fact sheets or the NCCIH herb database as a subject of clinical investigation.
The gap between traditional ethnobotanical use and the current evidentiary standard required for supplement health claims is substantial for this plant. While the traditional use record is genuine and historically significant, it does not, on its own, constitute evidence of clinical efficacy or safety by contemporary scientific standards.
References
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