Eupatorium perfoliatum—commonly called boneset—is a North American herb with a long record of use for fevers and “breakbone” aches during viral illnesses. Today it appears in teas, tinctures, and combination cold formulas. Lab studies suggest the plant’s extracts can influence inflammatory pathways and may interfere with viral processes, while traditional use points to diaphoretic (sweat-inducing) effects during febrile colds. However, boneset naturally accumulates pyrrolizidine alkaloids (PAs)—compounds that can harm the liver. Modern safety standards now limit PA contamination in teas and supplements, and there are no high-quality clinical trials proving boneset treats flu-like illnesses. This guide translates the research into practical, safety-first advice: what boneset is, how it is (and is not) used, what a “dose” really means today, who should avoid it, and what the evidence actually supports.
Quick Facts for Eupatorium perfoliatum
- Traditional fever herb; modern lab data show antiviral activity against dengue virus in cells.
- Contains hepatotoxic pyrrolizidine alkaloids; internal use is high-risk without verified PA testing.
- If used, choose products tested to EU PA limits (about 200–400 μg/kg depending on category) and keep use short-term only.
- Traditional tea used ~2 g dried aerial parts; no clinically established therapeutic dose.
- Avoid in pregnancy, breastfeeding, liver disease, or when using hepatotoxic drugs.
Table of Contents
- What is Eupatorium perfoliatum?
- Does boneset actually work?
- How to use boneset and dosage
- Variables that change effects
- Mistakes, interactions, and safety
- Who should avoid boneset?
- What the evidence says today
What is Eupatorium perfoliatum?
Eupatorium perfoliatum L. is a perennial member of the Asteraceae family native to wetlands and meadows across eastern and central North America. The distinctive “perfoliate” leaves—joined around the stem so the stem looks as if it pierces a single blade—explain the species name and help with field identification. Common names include boneset, feverwort, and thoroughwort. Historically, boneset tea was used during seasonal fevers and influenza outbreaks for its diaphoretic effects—encouraging sweating to reduce fever discomfort—and for generalized “breaking” of bone-deep aches.
Chemically, boneset is complex. The aerial parts contain:
- Flavonoids (e.g., quercetin derivatives and eupafolin), which are often studied for anti-inflammatory signaling effects.
- Sesquiterpene lactones (including guaianolides), a class with diverse bioactivity in other Asteraceae herbs.
- Caffeic-acid–based phenolics and plant polysaccharides that can modulate cell responses in vitro.
- Critically, boneset can contain pyrrolizidine alkaloids (PAs) such as lycopsamine and intermedine (including their N-oxides). Surveys of commercial boneset have measured wide PA variability across samples and preparations. Alcoholic tinctures and hot-water extractions can draw out these alkaloids, sometimes at levels that trigger regulatory concern. Because 1,2-unsaturated PAs are pro-toxic (metabolized to reactive pyrrolic intermediates), repeated exposure is linked to hepatic sinusoidal obstruction syndrome and genotoxic effects.
It’s also important not to confuse boneset with botanically related but distinct plants. For example, white snakeroot (Ageratina altissima) is a different species within the broader aster family and is historically associated with tremetol and “milk sickness,” not with boneset’s traditional fever use. Likewise, Joe-Pye weeds now assigned to the genus Eutrochium are different taxa from E. perfoliatum, even though older field guides sometimes lumped many “Eupatorium” species together. When purchasing, check the Latin binomial Eupatorium perfoliatum on the label.
In modern markets, boneset appears as dried cut herb for tea, single-herb tinctures, and multi-botanical cold formulas. Because PA carryover depends on species identity, harvest practice, and extraction method, quality control and independent PA testing are non-negotiable when assessing any internal product made from boneset.
Does boneset actually work?
Short answer: there’s no high-quality clinical evidence that boneset cures or prevents colds, influenza, or dengue. Most of what we know today comes from lab research and historical use—not randomized human trials.
What the lab work shows:
- Antiviral activity in vitro. A 2022 study reported that an ethanol extract of E. perfoliatum reduced dengue virus infection in liver-derived cells when used as a pre-treatment. The work linked effects to modulation of mTOR signaling and autophagy pathways and highlighted quercetin among potential actives. This points to plausible biochemical mechanisms, but in-cell results do not automatically translate to clinical benefit in people, especially given dosing limits imposed by PA safety.
- Inflammation-related pathways. Boneset contains flavonoids (e.g., eupafolin) and sesquiterpene lactones that influence inflammatory signaling in cell models. These include changes in nitric oxide synthase (iNOS) expression and cytokine/chemokine profiles. Such findings are mechanistic clues, not proof of symptom relief in febrile illnesses.
What we don’t have:
- Placebo-controlled human trials evaluating boneset alone for fever, aches, congestion, or recovery time. Historical popularity during influenza waves speaks to cultural use, not to modern, quantified efficacy.
- Validated clinical dosing that balances any benefit with the known risks of PA exposure. Even if antiviral or anti-inflammatory signals emerge in lab systems, human dosing must remain far below levels that increase PA risk.
The role of regulation and safety:
- The European Union now sets maximum PA levels for herbal infusions and supplements to protect consumers from chronic exposure. These limits address contamination risk; they do not endorse boneset as an effective treatment for any condition.
Bottom line: boneset’s promise remains preclinical. If you’re seeking evidence-based cold support, consider strategies with stronger human data (e.g., symptomatic care, vaccines for influenza when appropriate, hand hygiene, adequate sleep). If you still choose boneset for traditional reasons, treat it as a short-term, quality-controlled experiment—never a primary therapy—and prioritize PA-tested products.
How to use boneset and dosage
There is no clinically established therapeutic dose for boneset. Any internal use must be framed first by PA safety, then by traditional practice.
Forms you’ll see
- Tea (infusion/decoction): Dried aerial parts steeped in hot water. Traditional Western herbal sources describe a simple infusion prepared from the leaves and flowering tops.
- Tincture/Fluid extract: Hydroalcoholic extracts. Note that alcohol extracts can concentrate PAs, often more than teas.
- Combination formulas: Boneset paired with other herbs for seasonal symptoms.
What “dose” means today
- Traditional amount (context only): Some herbal references note ~2 g of dried aerial parts per serving of tea. This is not a recommendation; it’s a description of historical practice.
- Regulatory exposure limits (actionable today): Because the main risk is PA intake, the EU set maximum PA concentrations for products:
- Herbal infusions (dried product): around 200 μg/kg (some specific herb categories allow up to 400 μg/kg).
- Food supplements with herbal ingredients (including extracts): 400 μg/kg.
These limits are about contaminant control, not proven therapeutic dosing. They imply that if you use a boneset product at all, you should select one with independent lab certificates showing PA levels within or below the relevant category. - Duration: Keep any internal trial short (a few days), as PA risk relates to cumulative exposure. There are no data supporting long-term use.
How to choose and prepare
- Verify identity: Label must read Eupatorium perfoliatum (not “Eupatorium spp.”).
- Demand PA testing: Ask for a recent certificate of analysis (COA) quantifying the sum of 21 EU-listed PAs (and co-eluters) by LC-MS/MS. Prefer “non-detectable” where possible.
- Prefer tea over tincture if you insist on trying boneset, since water extracts can still carry PAs but tend to deliver less than hydroalcoholic tinctures.
- One-variable trials: If you test boneset tea for a few evenings during a feverish cold, avoid combining with multiple new supplements. Track how you feel, hydration, and any stomach or liver-related symptoms.
Practical guardrails
- Never for daily wellness or as a routine immune tonic.
- Avoid with alcohol or other hepatotoxic exposures; your liver doesn’t need the extra work.
- Stop immediately if you notice abdominal pain, nausea, dark urine, jaundice, or unusual fatigue.
Remember: the safest internal “dose” from a PA standpoint is zero. The only defensible scenario for short-term use is a PA-verified, identity-verified product, used briefly and conservatively.
Variables that change effects
Why do boneset products differ so much? Because several upstream choices profoundly affect what ends up in your cup or dropper:
1) Plant identity and chemotype
Even within E. perfoliatum, researchers have found wide PA variability (low- and high-alkaloid “chemotypes”). Misidentification or incidental admixture with other Eupatorium relatives can further shift chemistry. Work with suppliers who document voucher specimens and use DNA/chemical authentication.
2) Plant part and harvest timing
Leaves vs. flowering tops vs. stems differ in constituent balance. Alkaloid levels fluctuate with growth stage and stress. Reputable producers define the part used and standardize harvest windows.
3) Processing and extraction solvent
- Water vs. hydroalcoholic extraction: Alcohol generally extracts more PAs and sesquiterpene lactones. For a given herb mass, tinctures can deliver higher PA exposure than tea.
- Infusion vs. decoction: Longer boiling or steeping can increase total extraction (including unwanted PAs). Shorter infusions may modestly reduce PA intake but also lower beneficial phenolics—there’s a trade-off.
4) Dose, frequency, and duration
PA risk is mainly cumulative. Small amounts taken repeatedly or combined across sources (teas, spices, supplements) increase total exposure. EU maximum levels were set to help cap per-serving concentrations, but your real risk depends on how often and how long you consume PA-bearing products.
5) Product testing and transparency
High-quality brands share method-specific COAs listing the EU panel of PAs (including N-oxides) and reporting the lower-bound sum (the format regulators use). Look for batch-specific results (not a generic spec sheet), a recent test date, and a reputable third-party lab.
6) Your physiology
Liver health, genetics (drug-metabolizing enzymes), age, and concurrent medications change how your body activates or clears PAs. Individuals with reduced hepatic reserve or on drugs that stress the liver face disproportionate risk even at modest exposures.
Putting it together
When the goal is safety, the “best” boneset product is one that proves the least PA possible, not the highest extract potency. If a supplier can’t show credible PA data, choose another herb for fever comfort (e.g., non-PA botanicals or plain supportive care) rather than gambling on chemistry you can’t see.
Mistakes, interactions, and safety
Common mistakes
- Assuming “natural = safe.” PAs are natural yet genotoxic and hepatotoxic. Some boneset batches test near or above regulatory concern, especially extracts.
- Equating historical use with modern evidence. Popularity during past influenza waves doesn’t replace today’s safety standards or clinical trials.
- Using tinctures as a “stronger” option. Stronger extraction often means higher PA carryover—the wrong metric for a long-term organ risk.
- Daily preventive use. Boneset is not a daily immune tonic; any internal use should be brief and symptom-triggered at most.
- DIY wildcrafting without botany skills. Misidentification can introduce other toxic species or parts.
Potential interactions
- Hepatotoxic medications or alcohol: Additive liver strain (e.g., high-dose acetaminophen, certain antifungals, methotrexate, isoniazid, high alcohol intake).
- Drugs dependent on hepatic metabolism: Theoretically, PA-related liver injury can alter drug handling. If you take chronic medications, avoid boneset internally.
- Pregnancy and lactation: Avoid—PA exposure is unacceptable in these settings.
- Children and adolescents: Avoid; they are more vulnerable to contaminants per body weight.
Adverse effects to watch for
- Gastrointestinal: Nausea, cramping, diarrhea (especially with larger amounts or longer steeping).
- Hepatic: Right-upper-quadrant pain, dark urine, jaundice, unusual fatigue, poor appetite—seek medical care immediately.
- Allergy/cross-reactivity: Asteraceae plants can trigger contact or ingestion-related hypersensitivity in sensitive individuals.
Safer symptom support alternatives
If your priority is fever comfort and you’d rather avoid PA risk, consider non-PA strategies: adequate fluids and electrolytes, rest, light layers and tepid sponging for comfort, physician-approved antipyretics, saline nasal irrigation for congestion, and time. For botanical options, choose herbs without PA concerns and with better safety profiles, and discuss with your clinician.
Who should avoid boneset?
Given PA-related risks, the following groups should avoid internal boneset:
- Pregnant or breastfeeding individuals. Even low PA exposure is unacceptable, and safety data are lacking.
- People with any liver condition (past or present), abnormal liver tests, or a history of alcohol use disorder.
- Those taking hepatotoxic medications or multiple drugs metabolized through the liver.
- Infants, children, and adolescents. Body-weight–adjusted PA exposure and long-term risk make avoidance the prudent choice.
- Anyone without access to product testing. If you can’t verify a batch’s PA content via a recent COA, don’t ingest it.
- Individuals with Asteraceae allergies. Risk of hypersensitivity exists; avoid or proceed only with expert guidance.
What about topical use? Historically, topical applications have been explored in folk practice, but external exposure does not nullify risk—some PAs can absorb through skin, and damaged skin may absorb more. There is no compelling modern reason to use boneset externally when safer alternatives exist. If topical products are used for short, localized applications, insist on PA-tested material and avoid use on broken skin.
If you fall outside these categories and still intend to experiment with boneset, the safest path is short-term tea from a PA-tested batch, while monitoring for any liver-related symptoms and avoiding concurrent hepatotoxins. Discontinue at the first sign of adverse effects and consult your clinician.
What the evidence says today
Evidence strength: Low for efficacy; high for safety concerns.
- Efficacy: We have in vitro antiviral and inflammation-pathway data for E. perfoliatum constituents; we lack clinical trials demonstrating reduced symptom severity, illness duration, or prevention in humans. A single-herb, controlled human study has not established benefit for colds, influenza, or dengue. Extrapolating from cell data to human outcomes is inappropriate without dose-finding and safety-margin work.
- Safety: We have robust toxicological knowledge of pyrrolizidine alkaloids. Regulatory agencies now cap PA levels in herbal infusions and supplements to reduce chronic exposure. Surveys show that hot water and alcoholic preparations of boneset can extract meaningful amounts of PAs. This means any potential therapeutic signal must be balanced against an exposure that regulators explicitly seek to minimize.
- Regulatory context: In the EU, maximum PA levels are specified for herbal infusions (dried product) and for food supplements containing herbal ingredients. These caps exist because PA exposure is a population-level concern across teas, spices, and supplements—not because boneset is endorsed for treating illness.
Practical takeaway: Boneset remains a tradition-anchored herb with intriguing lab signals but no proven clinical benefits and a clear, well-characterized toxicological liability. If you want plant-based support during febrile colds, choose options with better safety profiles and human data, and always coordinate with your healthcare provider—especially if you have any liver considerations or take chronic medications.
References
- Potentially toxic pyrrolizidine alkaloids in Eupatorium perfoliatum and three related species. Implications for herbal use as boneset 2018 (Observational/Analytical)
- In-vitro antiviral action of Eupatorium perfoliatum against dengue virus infection: Modulation of mTOR signaling and autophagy 2022 (In vitro)
- Commission Regulation (EU) 2023/915 of 25 April 2023 on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006 2024 (Consolidated text) (Regulation)
- Pyrrolizidine Alkaloids in Foods, Herbal Drugs, and Food Supplements: Chemistry, Metabolism, Toxicological Significance, Analytical Methods, Occurrence, and Challenges for Future 2024 (Systematic Review)
- Boneset Uses, Benefits & Dosage 2025 (Clinical Overview/Traditional Dosing)
Disclaimer
This article is for general information and education. It is not a substitute for personalized medical advice, diagnosis, or treatment. Never start, stop, or combine herbs or medicines without discussing risks and benefits with a qualified healthcare professional who knows your medical history. If you develop symptoms of liver injury (abdominal pain, dark urine, jaundice, unusual fatigue), stop all supplements and seek medical care immediately.
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