Rubber rabbitbrush

Rubber Rabbitbrush (Ericameria nauseosa): An Encyclopedic Reference

1. Identity and Botanical Classification

1.1 Current Accepted Name and Synonymy

Ericameria nauseosa (formerly Chrysothamnus nauseosus), commonly known as chamisa, rubber rabbitbrush, and gray rabbitbrush, is a shrub in the sunflower family (Asteraceae) found in the arid regions of western North America. Rubber rabbitbrush was moved from the genus Chrysothamnus to the genus Ericameria in a 1993 paper. The second edition of the Jepson plant manual and the United States Department of Agriculture's Germplasm Resources Information Network have adopted the name Ericameria nauseosa. Because much of the scientific literature predates this reclassification, references to Chrysothamnus nauseosus are considered equivalent and are treated as such throughout this article.

One of the more recent transfers was Chrysothamnus nauseosus (Pall. ex Pursh) Britton, which is now known as E. nauseosa (Pall. ex Pursh) G.L. Nesom & G.I. Baird, from the section Macronema. The specific epithet means 'heavy scented'. Common synonyms include Chrysothamnus collinus, Chrysothamnus nauseosus subsp. nauseosus, and Chrysothamnus pallidus, among numerous varieties and infraspecific taxa.

1.2 Morphology

Ericameria nauseosa is a perennial shrub that can be as short as 10 centimeters (4 in) or as tall as 2.5 meters (8 ft 2 in); however, it is generally 0.6 to 1.5 m (2 to 5 ft). Both the flexible (rubbery) stems and the leaves are greenish-gray with a soft felt-like covering. It blooms from August to October and produces pungent-smelling, golden-yellow flowers. The flower heads are 6–13 millimetres (¼–½ in) long and made up of 5 small, yellow, tubular disk flowers, occurring in umbrella-shaped terminal clusters.

Rubber rabbitbrush is a western species that is extremely variable in appearance with a complex taxonomic status that includes 2 sub-species and 24 varieties. Two subspecies have been described: consimilis (the green form with 8 varieties) and nauseosa (the gray form with 14 varieties).

1.3 Native Range and Habitat

It is native from Saskatchewan to British Columbia south through the Great Plains and western states to Texas, Sonora, and Baja California, where it is typically found growing in sunny open areas with dry soils (sandy, gravelly, or clay) in a variety of habitats including the western plains, high desert, intermountain valley bottoms, foothills, and mountains. Rubber rabbitbrush is found in upland deserts or semi-deserts, sagebrush communities, and grasslands at elevations of 2,000 to 8,000 feet (609–2,438 m).

1.4 The Name "Rubber" and Latex Content

"Rubber" refers to the plant's sap, and "nauseosa" is a nod to its pungent scent. The plant contains a low-molecular-weight rubber latex in its stems and leaves. The natural rubber content ranged from 1–6.5% in the older wood, and the resin content in the new tissue ranged from 5–38%; the rubber content is inversely correlated with the resin content. During World War II, the U.S. Emergency Rubber Project investigated rubber rabbitbrush along with other native plants as potential domestic sources of natural rubber, since Southeast Asian rubber supplies were cut off by Japanese occupation. Extensive research was conducted, but the rubber content was found to be insufficient for commercial extraction given the technology of the time; the project was abandoned after the war, but interest in bio-based rubber has revived in recent decades.

2. Traditional and Historical Uses

2.1 Overview of Indigenous Use

Rubber rabbitbrush was used extensively by Indigenous peoples throughout its vast native range. Shoshone, Paiute, Navajo, Hopi, and numerous other peoples used different parts of the plant for practical and medicinal purposes. Ericameria species have been used ethnopharmacologically throughout history, and in reviewing the literature, one must consider reports regarding the use of different Ericameria species as well as Chrysothamnus species due to their phylogenetic relationship.

2.2 Medicinal Preparations and Specific Tribal Uses

Native Americans used rubber rabbitbrush for chewing gum, tea, cough syrup, and to treat chest pains.

Shoshone: The Shoshone Indians used steeped E. nauseosa leaves as a tea for colds, coughs, and stomach disorders, and also steeped dried E. nauseosa flowers and/or leaves as a general tonic.

Northern Cheyenne: The Northern Cheyenne Indians of Montana used E. nauseosa as a remedy for colds, coughs, and tuberculosis, and Indian tribes of Nevada boiled E. nauseosa roots and tops together for treating hematochezia (blood in the stool).

Navajo: The Navajo pounded the leaves into a lotion used to treat headaches, and also made a strong decoction of the roots taken for colds, fever, and to help with menstrual pain. In ceremonial medicine, the Navajo Kayenta and the Navajo Ramah used this plant as an emetic to cause vomiting. The Navajo also used rabbitbrush to produce a range of yellow dyes for wool and other fibers — different parts of the plant and different mordants produced colors from pale yellow through bright gold to deep olive green, and these dyes were important in the development of the Navajo weaving tradition.

Hopi and Paiute: The Hopi and Paiute prepared teas from the leaves to treat colds and coughs. The Hopi also used the plant as a dye and wove wedding belts with the branches.

Zuni: The Zuni used the blossoms of Ericameria nauseosa subsp. nauseosa var. bigelovii to make a yellow dye, and the stems to make baskets.

Arthritis and topical applications: Dried leaves and flowers were boiled in water to create a soak used to relieve pain and swelling caused by arthritis. Poultices from the plant material were applied to skin rashes and wounds. Decoctions from the stems and leaves were applied to ease toothache pain.

Ceremonial and other uses: Ceremonially, the plant may be used to treat someone who has been attacked or possessed by an unwanted spirit; Shoshone tradition uses it in this way to treat nightmares, though it is rarely discussed openly. The Tewa hung portions of the plant around the necks of babies to stop drooling. A gum obtained from the root was used for chewing. The leaves were used as a sanitary towel, especially after childbirth.

3. Key Constituents and Active Compounds

3.1 Major Chemical Classes

These plant species produce a considerable variety of secondary metabolites, including grindelane diterpenoids, labdane-type acids, flavonoids, coumarins, phenolic acids, and cinnamic acid derivatives, chromanones and acetophenones, polyacetylenes, and mono- and sesquiterpenes.

3.2 Grindelane Diterpenoids

Two new grindelic acid diterpenoids, 18-hydroxygrindelic acid and 18-succinyloxygrindelic acid, were isolated from Chrysothamnus nauseosus. The grindelane class of diterpenoids — named for their presence in the related genus Grindelia — are among the most structurally distinctive secondary metabolites of the plant. These resinous acids are concentrated in the stem and leaf tissues and are responsible in part for the plant's characteristic pungent odor.

3.3 Essential Oil Composition

Essential oil isolated from the aerial parts of E. nauseosa has been analyzed; the main (>2%) components were γ-decalactone (13.3%), cryptone (9.4%), terpinen-4-ol (9.3%), (E)-methyl cinnamate (6.0%), T-cadinol (4.7%), spathulenol (3.6%), 8Z-2,3-dihydromatricaria ester (3.1%), β-phellandrene (3.0%), p-cymen-8-ol (2.2%), 3-ethoxy-2-cycloocten-1-one (2.2%), and trans-p-menth-2-en-1-ol (2.1%). Distinctive features of the essential oil were the lactones (up to 15%) and polyacetylenes (up to 3.1%), including (2Z,8Z)-matricaria ester and 8Z-2,3-dihydromatricaria ester.

Gas-chromatography analysis found the essential oil to be predominantly enriched in monoterpenes (oxygenated monoterpenes 37.7%; hydrocarbons 10.0%), with the irregular monoterpene cryptone (9.4%) as the main constituent. Comparison with previous reports on E. nauseosa essential oils collected in other parts of the country suggested similar and unique components, indicating that the location where plants are collected affects their essential oil composition. Hydrodistillation of E. nauseosa aerial parts resulted in a yield of 1.3% (w/v) essential oil.

3.4 Flavonoids

Research into the flavonoid fraction of E. nauseosa has identified 11 flavones, four flavanones, and related compounds from the plant's dichloromethane extract. Other methoxylated flavonoids, as well as quercetin and luteolin, were also found present in the plant. These compounds are of particular scientific interest for their potential anticancer properties (see Section 4.3 below).

3.5 Polyacetylenes

Polyacetylenes constitute another pharmacologically noteworthy class in rubber rabbitbrush. Research on the related species C. nauseosus documented polyacetylenic compounds, and these have been identified more broadly across the Chrysothamnus genus. The relatively high amount of polyacetylenes in the essential oil may contribute to immunomodulatory activity, as these compounds have been characterized as potent immunomodulators.

4. Scientific Evidence by Area of Use

4.1 Immunomodulatory Activity

Analysis of pharmacological properties showed that essential oil isolated from E. nauseosa aerial parts was immunomodulatory and activated human neutrophils, leading to downregulated responses to subsequent activation by an inflammatory stimulus. Pharmacological studies showed that E. nauseosa essential oil activated human neutrophil Ca²⁺ influx, which desensitized these cells to subsequent agonist-induced functional responses. Based on previously reported data, nerolidol, β-pinene, spathulenol, sabinene, and γ-terpinene were identified as the most likely constituents contributing to this immunomodulatory activity. These studies suggest that essential oils may contribute to the beneficial medicinal properties reported for extracts from E. nauseosa.

Evidence strength: This evidence is preclinical and limited to in vitro cellular (neutrophil) assays. No human clinical trials have been conducted. Results are preliminary and exploratory.

4.2 Antimicrobial Activity

A distillate of E. nauseosa has been reported to have significant antimicrobial activity. Essential oil from C. nauseosus (Pall.) Britt. var. nauseosus has been reported to have antifungal activity against the plant pathogens Colletotrichum acutatum, C. fragariae, and C. gloeosporioides.

Evidence strength: These findings derive from laboratory (in vitro) studies. The antifungal targets reported are plant pathogens rather than human pathogens, and no clinical trials in humans are available. Evidence is preliminary and requires further investigation.

4.3 Anticancer (Melanoma) Activity

The PI3K/AKT and MAPK/ERK pathways are frequently mutated in metastatic melanoma; in a screen of over 2,500 plant extracts, the dichloromethane extract of Ericameria nauseosa significantly inhibited oncogenic activity of AKT in MM121224 human melanoma cells. This extract was analyzed by analytical HPLC, and compounds were subsequently isolated in a larger scale to afford 11 flavones (1–11), four flavanones (12–15), two diterpenes (16, 17), and a seco-caryophyllene (18). All isolated compounds were tested for activity, whereby only flavonoids were found active; of these, flavones were shown to be more active than the flavanones. The most potent flavone displayed an IC₅₀ of 14.7 ± 1.4 µM on AKT activity in MM121224 cells.

Flavonoids from E. nauseosa inhibited the phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT) pathway in human melanoma cells and were suggested as potential anticancer drugs. Two novel diterpenes were identified in the study, including (2S,5S,9R,10S,13S)-2-hydroxygrindelic acid, and a clerodane-type diterpene — notably the first report of a clerodane-type diterpene in the genus Ericameria.

Evidence strength: This research is conducted entirely in cell-line (in vitro) models of human melanoma. There are no animal studies or human clinical trials evaluating E. nauseosa extracts or isolated compounds in cancer patients. Evidence is very early-stage; results cannot be extrapolated to clinical efficacy.

4.4 Anthelmintic (Antiparasitic) Activity

In a screening of 40 methanolic plant extracts for anthelmintic activity against Haemonchus contortus, Ericameria nauseosa was among the 7 active extracts, and in further evaluation using the larval migration assay, E. nauseosa exhibited the highest activity, with an ED₅₀ value of 4.0 mg/ml. Three other extracts also showed inhibitory activity in the larval migration assay; these results support the need for additional evaluations of the nematocidal properties for at least these five plants.

Evidence strength: This is a single in vitro laboratory study using a veterinary parasite model (H. contortus affects small ruminants). There are no human anthelmintic trials. The evidence is preliminary.

4.5 Anti-inflammatory and Analgesic (Traditional Context)

The resins of rabbitbrush have shown potential anti-inflammatory properties in studies, and boiled leaves and flowers have been applied by various tribes to soak arthritic joints and reduce swelling and pain. The grindelane diterpenoids present in E. nauseosa are chemically related to grindelic acid, a compound identified in the closely related genus Grindelia that has been shown in separate research to modulate pro-inflammatory functions of respiratory epithelium and human macrophages. However, no dedicated in vitro, animal, or clinical anti-inflammatory studies have been published specifically on E. nauseosa extracts or isolated grindelane compounds from this species to date.

Evidence strength: Traditional use is well-documented ethnographically across multiple tribes. No direct human clinical or controlled laboratory evidence currently validates anti-inflammatory or analgesic effects in humans for this specific species.

4.6 Respiratory Conditions (Traditional Context)

Multiple indigenous groups independently used rubber rabbitbrush for respiratory ailments. The Shoshone Indians used steeped leaves as a tea for colds, coughs, and stomach disorders. The Northern Cheyenne Indians of Montana used E. nauseosa as a remedy for colds, coughs, and tuberculosis. No modern clinical studies have evaluated the efficacy of any preparation of this plant for respiratory conditions.

Evidence strength: Traditional/ethnobotanical evidence only. No clinical trials exist.

5. Body Systems and Health Areas Associated with Rubber Rabbitbrush

• Immune system: In vitro evidence of immunomodulatory activity via neutrophil Ca²⁺ signaling modulation.
• Oncology/dermatology (cellular): In vitro evidence of PI3K/AKT pathway inhibition in human melanoma cells.
• Respiratory system: Traditional use for colds, coughs, and tuberculosis (no clinical evidence).
• Musculoskeletal/analgesic: Traditional topical use for arthritis and pain (no clinical evidence).
• Gastrointestinal: Traditional use for stomach disorders, hematochezia, and as an emetic (no clinical evidence).
• Antiparasitic: Preliminary in vitro anthelmintic activity against H. contortus.
• Reproductive/gynecological: Traditional use for menstrual pain and post-partum care (no clinical evidence).

6. Dosage Forms and Reported Preparations

No standardized dosage forms for human use are recognized by any regulatory body or official pharmacopoeia. The preparations documented are exclusively from traditional ethnobotanical sources and research studies, as follows:

• Infusion/tea: The Shoshone steeped E. nauseosa leaves, or steeped dried flowers and/or leaves, as a general tonic or for colds, coughs, and stomach disorders.
• Decoction: A strong decoction of the roots was taken for colds, fever, and menstrual pain. Indian tribes of Nevada boiled roots and tops together for treating hematochezia.
• Topical soaks: Dried leaves and flowers were boiled in water to create a soak used to relieve pain and swelling caused by arthritis.
• Topical poultice/lotion: The Navajo pounded the leaves into a lotion used to treat headaches. Poultices from plant material were applied to skin rashes and wounds.
• Essential oil (research context): Hydrodistillation of aerial parts resulted in a yield of 1.3% (w/v) essential oil, used in laboratory studies of immunomodulatory and antimicrobial activity.
• Dichloromethane extract (research context): In the melanoma cell study, the dichloromethane extract of E. nauseosa was screened, then analyzed by analytical HPLC with the column effluent fractionated and tested for activity.
• Methanolic extract (research context): In the anthelmintic study, methanolic extracts of E. nauseosa were screened; the extract exhibited an ED₅₀ of 4.0 mg/ml in the larval migration assay.
• Chewing gum: A gum obtained from the root was used for chewing.

No human clinical dosages have been established, and no dosage recommendations appear in any peer-reviewed clinical study or official health body guidance.

7. Safety Considerations

7.1 General Safety Profile

There is little information regarding the biological activity and pharmacological properties of E. nauseosa. The absence of clinical safety data — including toxicology studies, adverse event reports, or pharmacokinetic data — means that the safety profile of rubber rabbitbrush for human consumption or topical use in supplement or therapeutic contexts has not been formally characterized.

7.2 Allergenicity and Latex Content

The species name "nauseosa" refers to the smell given off when the leaves or flowers are crushed, described as pineapple-like by some and foul and rubbery by others; the common name refers to the rubber content in the sap, which varies by subspecies. The plant's natural latex content raises theoretical concerns for individuals with latex sensitivity, though no clinical reports of cross-reactivity with E. nauseosa latex in latex-allergic individuals were identified in the sources reviewed.

Rubber rabbitbrush is being investigated as a source of hypoallergenic rubber for use in products designed for people allergic to latex. This investigation implies the compound makeup of its polyisoprene latex is distinct from that of Hevea brasiliensis, though its allergenicity has not been formally evaluated in published clinical studies.

7.3 Asteraceae/Compositae Family Sensitivities

As a member of the Asteraceae (Compositae) family, rubber rabbitbrush shares family membership with plants known to cause allergic contact dermatitis (e.g., ragweed, chrysanthemums). Individuals with known Asteraceae sensitivities may be at elevated risk of cross-reactive responses, though no specific case reports or controlled studies documenting contact dermatitis or allergic reactions from E. nauseosa preparations were identified in the primary scientific literature reviewed.

7.4 Emetic Properties

In ceremonial medicine, the Navajo Kayenta and the Navajo Ramah used this plant as an emetic to cause vomiting. This ethnobotanical report suggests the presence of compounds capable of inducing emesis, which is a relevant consideration in assessing safe intake amounts.

7.5 Geographic Variability of Constituents

Comparison with previous reports on E. nauseosa essential oils collected in other parts of the country suggested similar and unique components, indicating that the location where plants are collected affects their essential oil composition. This chemotypic variability means that the safety profile of one preparation may not necessarily apply to another prepared from plants of a different geographic origin or subspecies.

7.6 Absence from Major Regulatory Monographs

Rubber rabbitbrush does not appear in monographs published by the German Commission E, the European Scientific Cooperative on Phytotherapy (ESCOP), the World Health Organization (WHO) Monographs on Selected Medicinal Plants, or the European Medicines Agency (EMA). It is not listed in the NIH Office of Dietary Supplements fact sheets. No formal risk assessment has been conducted by any major regulatory or health authority to date.

8. Summary of Evidence Quality

The scientific investigation of rubber rabbitbrush is at an early, predominantly preclinical stage. Available evidence consists of:

• In vitro cellular studies demonstrating immunomodulatory effects on human neutrophils via essential oil fractions.
• In vitro cancer cell line (melanoma) studies demonstrating PI3K/AKT pathway inhibition by isolated flavonoids.
• In vitro anthelmintic activity against a veterinary nematode parasite.
• In vitro antifungal activity against plant pathogens (not human pathogens).
• Extensive ethnobotanical and historical use records across numerous Native American tribes for respiratory, gastrointestinal, pain, and gynecological conditions.

No randomized controlled trials, uncontrolled human clinical trials, or systematic reviews of clinical evidence exist for any therapeutic application of rubber rabbitbrush. All pharmacological findings are preliminary and exploratory. The gap between traditional use and scientific validation remains substantial.

References

• Schepetkin IA et al. "Phytochemical Composition and Biological Activity of the Essential Oil from Ericameria nauseosa Collected in Southwestern Montana, United States." Plants 13(15):2063, 2024. PMC/MDPI.
• Hell T et al. "Flavonoids from Ericameria nauseosa inhibiting PI3K/AKT pathway in human melanoma cells." Biomedicine & Pharmacotherapy 156:113754, 2022. ScienceDirect.
• Acharya J, Hildreth MB, Reese RN. "In vitro screening of forty medicinal plant extracts from the United States Northern Great Plains for anthelmintic activity against Haemonchus contortus." Veterinary Parasitology 201:75–81, 2014. ScienceDirect.
• Rose AF. "Grindelane diterpenoids from Chrysothamnus nauseosus." Phytochemistry 19:2689–2693, 1980. ScienceDirect.
• Hegazy M-EF et al. "Genus Chrysothamnus: A Source of Bioactive Compounds." Natural Product Communications 2(9):951–957, 2007. SAGE Journals.
• Ericameria nauseosa. Wikipedia. (Botanical identity, taxonomy, morphology, and range information; reviewed March 2026.)
• USDA NRCS. "Plant Guide: Rubber Rabbitbrush (Ericameria nauseosa)." USDA Plants Database.
• USDA NRCS. "Plant Fact Sheet: Rubber Rabbitbrush (Ericameria nauseosa)." USDA Plants Database.
• USDA Forest Service. "Rubber Rabbitbrush: Plant of the Week." US Forest Service Wildflowers.
• Zuni Ethnobotany. Wikipedia. (Documents Zuni use of E. nauseosa for dye and basketry.)
• Weber DJ et al. "Rubber Rabbitbrush (Chrysothamnus nauseosus): A Multi-Use Desert Shrub." SpringerLink.
• PlantNative. "Rubber Rabbitbrush (Chrysothamnus nauseosus)." PlantNative.org, 2026.
• Native Memory Project. "Rubber Rabbitbrush." NativeMemoryProject.org, 2020.