Boneset for Flu Like Fever - When, Why and How to Use This Bitter Diaphoretic
Boneset is not an everyday “immune herb.” It’s not something to sip all winter because you feel run down.
Its traditional job is much narrower: a hot, bitter infusion used for a stuck, influenza-like fever with chills, aches, and no sweat. That’s the lane.
Boneset for Flu-Like Fever makes sense only when you understand the traditional purpose for its use. The herb has a long history in North American herbal practice, but it also has clear limits. It’s strong, unpleasantly bitter, and easy to overdo.
The first colds of the season bring the same pitch. Take the mushroom blend, the greens powder, the zinc tower, and the elderberry gummies every morning until spring, and you will not get sick. Some of those have a purpose when a person is ill. None of them should be a season long go to. Boneset gets dragged into that pitch when a label calls it immune support. That is the wrong purpose for the plant. Eupatorium perfoliatum was a fever herb. Used hot, briefly, and then stopped, it matched an old pattern of care. Used as a daily tonic, it steps outside both the tradition and the safety file.
This is educational, not medical advice. Flu, COVID, pneumonia, and other infections can look alike early on. Get medical care when symptoms are severe, unusual, or not improving.
Boneset has a narrow traditional use for Flu Like Fever
Boneset is Eupatorium perfoliatum, also called thoroughwort by Samuel Thomson. Is a native North American plant in the aster family. The leaves appear pierced by the stem, which makes the Latin name `perfoliatum` easy to remember. That perfoliate leaf is the field mark. Late summer and early fall it carries flat clusters of dull white composite flowers. The part used in the old fever practice is the dried aerial herb, leaf and flowering top.
Herbalists have used the aerial parts, as a diaphoretic in fever formulas for a long time. Its reputation grew around illnesses with deep body aches, chills, and fever. Historical sources often connect it with influenza-like illness and “breakbone fever,” a term used for illnesses that caused severe aching, the deep bone and muscle ache of dengue-like and influenza-like illness.
Indigenous peoples of the eastern woodlands used it as a fever and cold remedy. That use carried it into settler households, then into Thomsonian, Eclectic, and Physiomedical practice, and into the United States Pharmacopeia from 1820 to 1916, where it was listed as a stimulant and diaphoretic.
Samuel Thomson’s note is short. He called thoroughwort warming and useful for cough and lung complaints, already a country tea. His larger system treated obstructed perspiration as a root problem. Cold, in that framing, checked the skin. Sweat stopped. Fever was the body’s attempt to restore heat and open that outlet. An illness that stayed chilly, deeply achy, and dry was incomplete. The point of a diaphoretic was to help the fever declare itself, drive a sweat, and reach the break of a fever. Trying to knock the fever down while the skin stayed cold and closed was the opposite move.
Later writers were more specific about the person in front of them. The classic picture was an intermittent or influenza-like fever with chills, a deep ache as if the bones were breaking, a coated tongue, nausea, and a sweat that would not come or would not finish. The hot infusion was a relaxant diaphoretic specific for that pattern. Large doses were frankly nauseating and, pushed far enough, emetic. Moderate doses of the warm tea were the household method. Dr. John R. Christopher worked in that same Thomsonian line. He kept diaphoretics for the stage when the skin needed to open and a fever needed to be brought on. Boneset sat in that acute kit. It was not food.
“Bring on the fever” did not mean make a well person ill. It meant help a smoldering, aching, non-sweating illness come to a proper sweat. Once the fever broke and the ache eased, the tea stopped. In Physiomedical terms the tissue state was not “low immunity.” It was an acute cold or tense state with a stuck fever. That is why the plant was chosen. A dry tickling cough with no fever is a different picture. A capsule taken from October to March is a different fad not a traditional purpose.
The traditional use is very specific.
A person is hot, chilled, achy, and dry-skinned. They feel like the fever is locked inside. They can’t get warm, but they aren’t sweating either. In that moment, old herbal practice used hot diaphoretic tea, warm blankets, and rest.
A diaphoretic is an herb used to support sweating. In traditional Western herbalism, diaphoretics are often matched to the fever pattern. Some are gentle and pleasant, like elderflower or yarrow. Boneset is different. It’s bitter, stronger, and better reserved for the right picture.
That matters because fever is not one simple thing.
A fever can come with chills, sweating, thirst, agitation, weakness, respiratory symptoms, digestive symptoms, or a stiff neck. Those are different situations. Treating every fever with the same herb is bad herbal thinking.
Boneset is best understood as an herb for a short window, not a long season.
The traditional use is not:
Daily immune support
A pleasant winter beverage
A food herb
A general cold remedy
A replacement for medical care
A way to “sweat out” every illness
A diaphoretic is not a winter tonic, and a broth is not a flu stack.
That one sentence can prevent a lot of misuse.
A bitter hot cup is the point
Boneset tea is not supposed to taste good. The bitterness is part of the experience.
Boneset contains bitter compounds, including sesquiterpene lactones. Bitter herbs can stimulate the mouth, stomach, and nervous system in ways that affect digestion and body response. In the fever context, traditional herbalists cared less about making it tasty and more about using a hot, strong-tasting infusion to move the body toward sweating.
That doesn’t mean “more bitter means better.” It means the herb itself is bitter and should be respected.
A classic boneset preparation is a hot infusion, not a long-boiled decoction. The dried herb is steeped in hot water, covered, and taken warm. Covering the cup helps keep the volatile parts from drifting off with the steam.
The “hot” part matters. A cold extract may still taste bitter, but it doesn’t play the same traditional role. Boneset’s fever use belongs with warmth:
Hot tea
Warm bed
Covered body
Rest
Fluids
Close symptom watching
The goal is not to force a dramatic sweat. The goal is to help a stuck fever break into a light, steady perspiration.
A reasonable traditional pattern looks like this:
The person has chills, aches, and fever.
Skin feels dry.
They aren’t sweating much.
They drink a small cup of hot boneset infusion.
They get under covers and rest.
Sweating begins.
Fever reaches its max, then recedes
Stop pushing the herb and focus on fluids and recovery.
That last step matters. Once sweating starts, a fever has broken, more boneset is not automatically better.
The picture is specific. Feverish. Deeply achy. Chilled, or alternating chill and heat. Skin not sweating in proportion to the heat, or a low grade fever that will not break. Use leaf and flower, not a mystery root product. About 1 to 2 grams of dried herb, roughly a teaspoon of cut leaf, in a cup. Pour just-boiled water over it, cover, and steep 10 to 15 minutes so the aromatic fraction stays in the cup. Strain. Drink it warm. One to three cups across a day, only while that picture holds.
The covered steep is practical, not ceremonial. You want the vapor in the cup. You also want the person warm enough to sweat. The tea does not do that work alone. If you are going to support a sweat, give the body the conditions for a sweat. Then let it finish.
Boneset has a reputation for causing nausea when taken strong or in large amounts. Some traditional texts even describe purposely using it to induce vomiting at high doses. That is not a goal in home fever care, that is using this herb as an emetic. Inducing vomiting during a flu-like illness can raise the risk of dehydration and make everything harder.
So the rule is simple: use small amounts, use it briefly, and stop if it makes the stomach turn.
What “stuck fever” means in plain language
A stuck fever is not a formal medical diagnosis. It’s an herbal description.
It usually means a fever that feels locked up; low grade with chills and aches, where the body hasn’t moved into sweating yet. The person may say:
“I’m freezing, but I know I have a fever.”
“My skin feels dry and hot.”
“My whole body aches.”
“I can’t get comfortable.”
“I feel like I need to sweat, but I can’t.”.
Once there is fever and sweating, boneset is less relevant. When the person is weak, clammy, depleted, vomiting, confused, short of breath, or dehydrated, boneset is the wrong focus. Those situations need support, fluids, monitoring, and often medical care.
Fever itself still needs informed judgment. A short course of boneset tea does not replace a medical visit. High fever, stiff neck, confusion, trouble breathing, chest pain, a fever that will not break after a few days, or illness in an infant or an older adult are all reasons for a clinic visit, not taking an herb for a week.
The limits
A short course means days, not weeks. Three to five days is a reasonable outer limit for an otherwise healthy adult, then stop, whether you feel entirely finished or not. Do not taper the jar into a tonic. Do not keep a cup just in case when the next person in the house coughs. The diaphoretic job is over when the sweat has come and the bone ache has eased. Lingering tiredness after a fever is convalescence. It is fed with broth, ordinary food, and rest. It is not an indication for more boneset.
This limit is traditional, and it is now also a safety limit. Boneset contains unsaturated pyrrolizidine alkaloids (PAs), mainly lycopsamine and intermedine, their N-oxides, and related forms. The American Herbal Pharmacopoeia confirmed them in authenticated herb and in teas and tinctures made the old way. Levels are often low beside notorious PA plants. They still extract into water, and they still exceeded interim European limits for herbal products. Unsaturated PAs are metabolized in the liver to reactive pyrroles. Over time, and at higher exposure, the class effect is injury to hepatic venules, plus a cancer signal in animal work. Direct case reports of boneset liver failure are lacking. That absence is not a free pass. Clearance depends on hepatic glutathione systems that are not equal in every person.
So the cold tonic use is retired. A bitter cup for digestion was an old Eclectic habit. It is also repeated exposure for a complaint that does not need this plant. Bitters with a cleaner record exist. Boneset does not get to be one of them.
Safety
Skip it in pregnancy, nursing, infants, and children. Skip it with liver disease, unexplained elevated liver enzymes, or heavy daily alcohol use. Skip it alongside drugs that already load the liver. Asteraceae allergy is a practical stop. If ragweed, chamomile, or feverfew swells the mouth or closes the chest, do not test this tea. Nausea is a stop signal, not proof that the diaphoretic is working. The old emetic dose is not a goal.
When boneset is the wrong herb
Boneset has limits. Respecting those limits makes the herb more useful, not less.
Do not use boneset as a long-term tonic. Do not drink it daily for prevention. Do not use it because everyone in the house is sick and you feel nervous. Do not use it in children, pregnancy, breastfeeding, liver disease, or complex medical situations unless a qualified clinician says it fits.
There are two main safety concerns.
The first is nausea and vomiting. Boneset is famous for this when overused. If nausea appears, stop.
The second is liver safety uncertainty. Some plants in the Eupatorium group have raised concern because certain related species can contain pyrrolizidine alkaloids, a class of compounds linked with liver toxicity. Commercial quality and species identification matter. This is one more reason not to wildcraft casually or use boneset for long periods.
People with ragweed or aster-family allergies should also be cautious. Boneset belongs to the aster family, along with ragweed, chamomile, echinacea, yarrow, and many daisies. Allergy patterns vary, but the family connection matters.
Medication interactions are not well mapped. That does not mean there are none. It means caution wins, especially with prescription medications, liver conditions, immune conditions, or blood-thinning drugs.
Red flags need medical care
A flu-like fever can be ordinary. It can also turn serious.
Get medical help fast for:
Trouble breathing
Chest pain or pressure
Blue or gray lips
Severe weakness
Confusion
Fainting
Stiff neck
Seizure
Signs of dehydration
Fever that is very high or not improving
Fever in an infant
Symptoms that improve, then come back worse
Ongoing vomiting
Worsening cough or shortness of breath
Higher-risk people should call a clinician early in the illness. This includes adults over 65, pregnant people, infants and very young children, and people with asthma, COPD, heart disease, diabetes, kidney disease, immune suppression, or other chronic conditions.
Herbs should not delay antiviral treatment when flu is likely and risk is high. They should not delay testing when COVID is possible. They should not delay antibiotics when pneumonia or another bacterial infection is suspected.
Use a thermometer, not vibes
Fever care goes better when you track what is happening.
Write down:
Temperature
Time
Sweating or chills
Fluids taken
Urine output
Medicines used
Herbs used
Breathing symptoms
Any worsening signs
This helps you make better decisions. It also helps a clinician if you need care.
Don’t guess based only on how hot someone feels. Use a thermometer. Touch is not reliable enough.
Nutritional support, Broth helps recovery
Fever raises fluid loss. Breath is faster. Sweat, if it finally comes, takes water and sodium with it. Appetite drops. The first nutritional job is to replace what is leaving, in a form the stomach will accept whether that is plain water or a fortified broth.
Water matters, and water alone is often not enough once sweating starts. Salt is the part people skip. A little sodium in the cup helps the fluid stay on board. Warm fluid empties more comfortably than a cold drink when someone is chilled and nauseated. Small mugs, taken often, beat a forced quart.
Broth has a place during illness. It gives warm fluid, salt, and a little nourishment. It can feel comforting when appetite is low. Chicken soup has earned its reputation because it’s easy to tolerate and helps with hydration.
But a nutritional broth and boneset tea are not doing the same job.
Boneset tea is a targeted traditional diaphoretic. Broth is supportive food.
The nutritional support after the tea did its job is salted chicken broth. Use bony chicken pieces, or a small bird cut up. Cover with cold water by about two inches. Add one onion, two carrots, two celery stalks, two or three cloves of garlic, and a small handful of parsley stems. Salt it so it tastes like food. Bring it just until it shivers, then hold it below a boil for 2 to 3 hours. Skim the gray foam early. Strain. Chop the parsley leaves in at the end if you want the fresh green. Sip it warm, by the mug, several times across the day. Eat the vegetables if they are still pleasant.
This pot is doing the supportive work. Fluid. Sodium, because you added it. A little potassium and other minerals from the onion, carrot, and celery. Some protein and fat from the chicken, more if a few soft pieces stay in the cup. If the simmer pulls gelatin from the joints and skin, the cooled broth may set. That gel is partially hydrolyzed collagen, rich in glycine and proline, low in tryptophan. A mug can give a few grams of that protein. It is not a measured collagen dose, and it is not a complete protein. It goes down easy, which is the point.
Hot chicken soup has a modest record beyond kitchen habit. It has been shown to speed mucus movement, and in a lab model it slowed neutrophil chemotaxis a little more than hot water alone. That is not an antiviral. It is a reason the traditional cup is reasonable care while you wait the illness out. Do not load the pot with boneset. Do not load it with mushroom powder. The herb and the meal stay apart so you can stop one without losing the other.
If meat is refused, just make the same vegetables, garlic, and parsley, and salt them well. A fever does not require a perfect amino-acid profile. It requires fluid that will be drunk.
Why “flu stack” thinking causes problems
A stack sounds powerful. In practice, it can turn into a pile of herbs that don’t belong together.
This is also why the seasonal stacks fail. A mushroom megadose, a greens powder, and a vitamin tower ask a queasy stomach to process more when its already working. Turkey tail and other polypores are all over that pitch. Food mushrooms in a soup are food. A seven-mushroom capsule from October to April is a different claim. It is the claim that a stack can stand in for sleep, electrolytes, and a week of rest. Boneset is not doing that job either. A diaphoretic used for a few days is not a beta-glucan product stack, and a beta-glucan product stack is not a purpose chosen tea.
During acute illness, the body is already under stress. The stomach may be sensitive. The liver is already processing inflammatory chemicals, medicines, and whatever else is taken. Adding many herbs at once makes it harder to know what helped, what caused nausea, and what needs to stop.
Boneset should not be buried under:
Multiple immune tinctures
Strong bitters
Alcohol-heavy extracts
Spicy heating herbs
High-dose supplements
Random powders from the back of the cabinet
That’s not careful herbalism with a purpose. That’s panic mixing.
Trying to turn broth into a “flu stack” misses the point. It also makes dosing messy. If you cook a strong medicinal herb into a pot of broth, it becomes hard to know how much each bowl contains. That’s a bad fit for an herb like boneset, which can cause nausea and should not be taken casually.
Keep the categories clean.
Use boneset tea when the traditional picture fits | Use broth when the body needs support |
Fever with chills, aches, and dry skin | Low appetite |
No sweat yet | Fluid and salt need |
Short-term use | Gentle nourishment |
Bitter hot infusion | Warm food |
Stop once sweating starts or nausea appears | Continue as tolerated |
That’s the practical split.
A good fever-care setup might include both, but not blended into one heroic potion.
For example:
Boneset tea may be used briefly during the stuck, chilled, achy stage.
Water or electrolyte drinks help prevent dehydration.
Broth comes later or between cups when appetite is low.
Plain food returns when hunger returns.
Medical care comes in when red flags show up.
That’s clean and sensible.
Pick a clear goal. If the goal is to support sweating during a stuck fever, use the diaphoretic approach briefly. If the goal is hydration, drink fluids. If the goal is calories and nutritional support, use broth. If the goal is antiviral treatment, talk with a herbalist or a clinician, especially early in the illness.
The Centers for Disease Control and Prevention notes that flu antivirals work best when started early, usually within the first couple of days of symptoms. People at higher risk should not wait around trying herbs first. That includes older adults, pregnant women, very young children, and people with chronic health conditions being managed with medication.
How to prepare boneset without turning it into a project
Use dried boneset from a reliable herb supplier. That is safer than guessing from a field guide when sick. Wildcrafting medicinal plants takes real skill, and the aster family includes many similar-looking plants.
The plant name matters. Look for Eupatorium perfoliatum. Don’t assume every plant called boneset, thoroughwort, or feverwort is the same thing. Common names are messy and unreliable.
A simple preparation looks like this:
Put a small amount of dried boneset in a mug or teapot.
Pour hot water over it.
Cover it while it steeps.
Strain it.
Drink it warm.
Rest under covers.
Stop when the fever moves into sweating or the body says no.
Follow the label on the product you bought, or work with a qualified herbalist. Don’t increase the amount because the tea tastes medicinal. Stronger is not smarter here.
Boneset is often described as more nauseating when taken hot and strong. Since hot use is part of the traditional fever method, the answer is not to make a giant mug and force it down. The answer is modest use.
If the taste makes you gag, don’t fight your body. There are gentler diaphoretics.
What to pair with it
Good pairings are basic.
Use:
Water
Electrolytes if sweating a lot
Light broth
Rest
Warm blankets
A thermometer
Testing when COVID or flu is possible
Medical advice when risk is higher
Skip:
Alcohol
Heavy meals if nauseated
Extra bitter herbs
Overheating the room
Sauna use during fever
Exercise to “sweat it out”
Long, repeated dosing
Sweat is fluid loss. If a fever starts sweating, the next job is hydration. Dry mouth, dizziness, dark urine, low urine output, or a racing heart can point toward dehydration. Don’t keep pushing diaphoretics when the body needs fluids.
What about tincture
Boneset tincture exists, but it doesn’t match the same traditional logic as a hot cup.
A tincture may deliver the herb, but it does not deliver warmth, bitter flavor and fluid in the same way. It may also contain alcohol, which is not helpful when someone is feverish, dehydrated, or taking medications.
For the old fever indication, tea makes more sense than tincture.
That doesn’t make tincture useless in every context. It just means the form should match the purpose. For a hot diaphoretic approach, hot infusion is the cleaner choice.
The best way to think about boneset
Boneset makes the most sense when you treat it like a short-term tool with a specific purpose.
Not a pantry staple for every sniffle. Not a daily tonic. Not a broth ingredient. Not a cure for influenza. Not a reason to avoid testing, medical advice, or rest.
Its traditional lane is clear:
Flu-like low grade fever that wont break
Chills and deep aches
Dry skin
Little or no sweating
Hot bitter infusion
Brief use
Stop when sweating starts, fever rises then breaks or nausea appears
That’s it.
The discipline is in staying inside that lane.
A good home fever plan is simple. Keep fluids close. Rest. Use a thermometer. Eat light if hungry. Use broth for nourishment to support recovery. Consider boneset with prupose, only if the old diaphoretic picture fits. Watch for red flags. Get medical help early when the person is high risk or symptoms look serious.
Seasonal mega-stacks sell a fear of the next cough. They are easy to market and hard to stop, because the dose has no clear picture and no end date. Boneset has both. The picture is a closed-skin, bone-aching fever. The end date is the sweat, or five days, whichever comes first. Broth has a picture too. Thirst, salt loss, a stomach that will not take a meal. It ends when ordinary food returns.
Keep the tools separate. The herb is a short diaphoretic for a stuck influenza-like fever. The broth is salted chicken, onion, carrot, celery, garlic, and parsley, sipped through the day. The tea is hot, covered, and done when the sweat breaks. The limit is the point.
Boneset has earned a place in traditional herbal medicine because it does one job well when used with purpose and care. Peace
All information provided on this website, including blog posts, articles, and any related content, is for general informational and educational purposes only. It is not intended to diagnose, treat, prescribe, cure, mitigate, or prevent any medical condition or disease. Always consult a qualified healthcare provider before making any changes to your health regimen, including the use of herbs, teas, foods, or supplements discussed here. The author is not a licensed medical professional, and this content does not replace professional medical advice, diagnosis, or treatment. The author and One Stop Apothecary are not responsible or liable for any adverse effects, consequences, or outcomes resulting from the application or use of any suggestions, preparations, or information presented herein. Any use of this material is at the reader's own discretion and sole responsibility. These statements have not been evaluated by the Food and Drug Administration (FDA). This information is not intended to diagnose, treat, cure, or prevent any disease.
Sources
American Herbal Pharmacopoeia Publishes Boneset Monograph and Therapeutic Compendium (HerbalGram / American Botanical Council)https://www.herbalgram.org/resources/herbalgram/issues/125/table-of-contents/hg125-orgnews-ahpboneset/
Boneset monograph excerpt (American Herbal Pharmacopoeia, hosted summary PDF; traditional use, Thomsonian and Eclectic record, USP and National Formulary listing)https://www.uni-muenster.de/imperia/md/content/pharmazeutische_biologie2/institut/meldungen/boneset_monograph_081919_reduced.pdf
Potentially toxic pyrrolizidine alkaloids in Eupatorium perfoliatum and three related species. Implications for herbal use as boneset — Colegate et al., Phytochemical Analysis, 2018https://pubmed.ncbi.nlm.nih.gov/29968391/
Boneset Uses, Benefits & Dosage (Drugs.com Natural Products; no clinical dose, traditional 2 gram figure, PA caution)https://www.drugs.com/npp/boneset.html
Eupatorium perfoliatum L.: Phytochemistry, traditional use and current applications — Hensel et al., Journal of Ethnopharmacology, 2011https://www.sciencedirect.com/science/article/abs/pii/S037887411100729X
Antiviral activity of hydroalcoholic extract from Eupatorium perfoliatum L. against the attachment of influenza A virus — Derksen et al., Journal of Ethnopharmacology, 2016https://pubmed.ncbi.nlm.nih.gov/27178637/
Thorough-Wort, Boneset — Eupatorium perfoliatum (Dr. Thomson) (The Thomsonian System of Medicine)https://www.chestofbooks.com/health/materia-medica-drugs/The-Thomsonian-System-Of-Medicine/Thorough-Wort-Boneset-Euparorium-Perfoliatum-Dr-Thomson.html
Eupatorium. Boneset (A Practitioner’s Handbook of Materia Medica and Therapeutics, T. S. Blair)https://www.chestofbooks.com/health/materia-medica-drugs/A-Practitioner-Handbook-Of-Materia-Medica-and-Therapeutics/Eupatorium-Boneset.html
Boneset (Georgia Southern physic garden, quoting Maud Grieve, A Modern Herbal, 1931, on breakbone fever and the domestic infusion)https://ww2.georgiasouthern.edu/finops/facilities/landscape-services/arboretum/major-collections/physic-garden/boneset/
Boneset (Eupatorium perfoliatum) (Herbal Reality)https://www.herbalreality.com/herb/boneset/
Eupatorium perfoliatum (Flora of North America; perfoliate leaf, sessile bases)https://floranorthamerica.org/Eupatorium_perfoliatum
Chicken Soup Inhibits Neutrophil Chemotaxis In Vitro — Rennard et al., Chest, 2000https://www.sciencedirect.com/science/article/abs/pii/S0012369215377217
Effects of Drinking Hot Water, Cold Water, and Chicken Soup on Nasal Mucus Velocity and Nasal Airflow Resistance — Saketkhoo, Januszkiewicz, and Sackner, Chest, 1978https://www.sciencedirect.com/science/article/abs/pii/S0012369215373876
The Christopher line is the OSA guidance read through the Thomsonian source above, not a separate Christopher monograph on boneset. The AHP record is tighter on the official listing than the blog sentence: the infusion was in the United States Pharmacopeia from 1820 through 1900, then in the National Formulary from 1916 through 1946.
Additonal source links
Boneset’s traditional use and research background: Hensel et al., “Eupatorium perfoliatum L.: Phytochemistry, traditional use and current applications” — PubMed
Laboratory findings on influenza A: Derksen et al., “Antiviral activity of hydroalcoholic extract from Eupatorium perfoliatum L. against the attachment of influenza A virus” — PubMed. This is lab research, not evidence that Boneset treats flu in people.
Pyrrolizidine alkaloids in Boneset samples: “Dehydropyrrolizidine alkaloids in the North American medicinal herb Eupatorium perfoliatum and related species” — PubMed
Safety guidance on pyrrolizidine alkaloids in herbal products: European Medicines Agency, “Public statement on the use of herbal medicinal products containing toxic, unsaturated pyrrolizidine alkaloids” — EMA
Flu symptoms and care: U.S. Centers for Disease Control and Prevention, “Flu: Symptoms and Treatment” — CDC
Comments