Herb & supplement monograph

Coltsfoot Drug Interactions, Uses, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Coltsfoot interacts with medications. The heart of this page is the interaction list — every drug Coltsfoot is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Coltsfoot is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Coltsfoot Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Coltsfoot drug interaction appears low for most people, since no interaction has been confirmed in human studies. None of the listed interactions are rated major, and all of them rest on lab findings or theory rather than well-documented effects in people.

Interactions deserving the most attention

The combination we would watch most closely is coltsfoot with blood thinners such as warfarin, aspirin, clopidogrel, or heparin, because coltsfoot has been reported to reduce platelet clumping, which could add to bleeding risk. We would also be cautious with drugs that speed up a liver enzyme, including seizure medicines like carbamazepine, phenytoin, and phenobarbital and the antibiotic rifampin, since they may increase the conversion of coltsfoot's natural alkaloids into liver-toxic byproducts. In high doses, coltsfoot could also theoretically work against blood pressure medications.

What the rest of the list means

The long list of interacting medications largely reflects a few broad drug categories rather than hundreds of separate proven problems. Nearly all of these concerns come from laboratory research or predicted effects on how the body processes medicines, and none has been clearly shown to cause meaningful harm in people.

Check your medications against Coltsfoot

Based on HelloPharmacist’s Coltsfoot interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Coltsfoot

374 medications have a known interaction with Coltsfoot, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Coltsfoot using our pharmacist-reviewed interaction data.

AI summaries are generated from our Coltsfoot interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Coltsfoot combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Coltsfoot affects

Every type of medication (drug category) Coltsfoot is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 3 drug categories Coltsfoot interacts with

Anticoagulant/antiplatelet DrugsAntihypertensive DrugsCytochrome P450 3a4 (cyp3a4) Inducers

Anticoagulant/Antiplatelet Drugs

Concomitant use might increase the risk of bleeding due to decreased platelet aggregation. Coltsfoot has been reported to inhibit platelet aggregation; avoid concomitant use. Some of these drugs include aspirin, clopidogrel (Plavix), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, ticlopidine (Ticlid), warfarin (Coumadin), and others.

Likelihood Possible Evidence D

Antihypertensive Drugs

Theoretically, excessive doses of coltsfoot may interfere with antihypertensive or cardiovascular therapy.

Likelihood Possible Evidence D

Cytochrome P450 3A4 (Cyp3A4) Inducers

Hepatotoxic pyrrolizidine alkaloids (PA) are substrates of cytochrome P450 3A4 (CYP3A4). Theoretically, drugs that induce CYP3A4 might increase the conversion of PAs to toxic metabolites. Some drugs that induce CYP3A4 include carbamazepine (Tegretol), phenobarbital, phenytoin (Dilantin), rifampin, rifabutin (Mycobutin), and others.

Likelihood Possible Evidence D

Monograph

Coltsfoot: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Coltsfoot is a traditional herb long used to soothe coughs and clear mucus, but solid human evidence for these uses is lacking. More importantly, the raw plant can contain liver-toxic pyrrolizidine alkaloids, so it carries real safety concerns and is best avoided unless you use a product certified to be free of these compounds.

Scientific name: Tussilago farfara
Family: Asteraceae
Part used: Leaves and flowers
Common forms: Tea, dried herb, tincture, syrup, capsules, lozenges

People commonly use it for

Cough
Sore throat
Bronchitis and congestion
Loosening mucus (expectorant)
Asthma symptoms

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

May contain liver-toxic pyrrolizidine alkaloids; use only certified PA-free products, if at all.

PregnancyLikely Unsafe

When products containing hepatotoxic pyrrolizidine alkaloid (PA) constituents are used orally. Coltsfoot preparations containing hepatotoxic pyrrolizi...

Read the full pregnancy detail

BreastfeedingLikely Unsafe

When used orally. Hepatotoxic pyrrolizidine alkaloid (PA) constituents in coltsfoot are excreted in milk. There is insufficient reliable information a...

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Coltsfoot (Tussilago farfara) is a perennial herb native to Europe and parts of Asia, and it now grows in many areas of North America as well. It is named for its leaves, which are shaped a bit like a calf's foot. The plant produces bright yellow flowers that look like small dandelions, though it is not related to them.

For centuries, people have used coltsfoot in traditional and folk medicine, mainly as a remedy for coughs and breathing problems. In fact, one of its old names is "coughwort." The leaves and flowers are typically dried and made into teas, syrups, tinctures, or lozenges.

While it has a long history of use, modern science has raised important safety concerns about this herb, which we cover below.

Uses & effectiveness

Coltsfoot is most often used as a cough remedy and to soothe an irritated throat. People also use it for chest congestion, bronchitis, and asthma symptoms, with the idea that it acts as an expectorant to help loosen and clear mucus.

It is important to be honest: there is very little reliable human research showing that coltsfoot works for any of these conditions. Most of the support comes from traditional use and a small amount of laboratory or animal research. This kind of early evidence cannot tell us whether coltsfoot is truly safe or effective in people.

Because the possible benefits are unproven and the safety risks are real, many health authorities suggest choosing safer, better-studied options for coughs and congestion.

How it works

Coltsfoot contains mucilage, a gel-like substance that may coat and soothe an irritated throat, which could explain its traditional use for coughs. It also contains flavonoids and other plant compounds that have shown some anti-inflammatory activity in laboratory studies.

These proposed effects are mostly based on test-tube and animal research, not on strong human studies. So while the ideas behind its use are reasonable, they have not been clearly proven in people.

The herb also naturally contains pyrrolizidine alkaloids (PAs). These are the compounds responsible for its main safety concern, not its supposed benefits.

Safety & precautions

The biggest concern with coltsfoot is that it can contain pyrrolizidine alkaloids (PAs), which are known to be toxic to the liver. Repeated or long-term use has been linked to serious liver damage, and PAs may also harm an unborn baby. Some products are processed to remove these alkaloids and may be labeled "PA-free" — only such products should be considered, if any.

Avoid coltsfoot if you have liver disease, drink alcohol heavily, or have a history of liver problems. People who are allergic to plants in the daisy/ragweed family (Asteraceae) may also react to it.

Pregnancy: Avoid coltsfoot. The pyrrolizidine alkaloids can be dangerous and may harm the developing baby.

Breastfeeding: Avoid coltsfoot. Toxic compounds may pass into breast milk and harm a nursing infant.

Do not give coltsfoot to infants or children. Always talk with your pharmacist or doctor before using it.

Side effects

When used short-term, some people may tolerate coltsfoot, but reliable safety information is limited. Possible side effects include allergic reactions, especially in people sensitive to ragweed, daisies, marigolds, or chrysanthemums.

The most serious concern is liver toxicity from pyrrolizidine alkaloids. This can show up as unusual tiredness, nausea, abdominal pain, dark urine, or yellowing of the skin or eyes (jaundice). If you notice any of these symptoms, stop using the product and seek medical care right away.

Coltsfoot: Reported Adverse Effects

Documented safety reports on Coltsfoot from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

Orally, the major concern with coltsfoot use is its pyrrolizidine alkaloid (PA) content. These alkaloids can cause liver and lung injury. Chronic exposure to other plants containing hepatotoxic PA constituents has been associated with hepatic veno-occlusive disease. Sub-acute veno-occlusive disease can cause vague symptoms, including colicky pains, vomiting, diarrhea, and ascites within several days; persistent liver enlargement occurs within a few weeks. Deep vein thrombosis (DVT) and pulmonary embolus (PE) thought to be associated with coltsfoot have been reported. Coltsfoot products containing PAs should be avoided. There is currently a limited amount of information available about the adverse effects of PA-free coltsfoot.

Chojkier M. Hepatic sinusoidal-obstruction syndrome: toxicity of pyrrolizidine alkaloids. J Hepatol 2003;39:437-46.
Roeder E. Medicinal plants in Europe containing pyrrolizidine alkaloids. Pharmazie 1995;50:83-98.
WHO working group. Pyrrolizidine alkaloids. Environmental Health Criteria, 80. WHO: Geneva, 1988.
Freshour JE, Odle B, Rikhye S, Stewart DW. Coltsfoot as a potential cause of deep vein thrombosis and pulmonary embolism in a patient also consuming kava and blue vervain. J Diet Suppl 2012;9:149-54.

Reports by condition

Diarrhea Hepatic

Orally, coltsfoot might cause liver damage. Coltsfoot contains hepatotoxic pyrrolizidine alkaloids (PAs). Chronic exposure to other plants containing hepatotoxic PAs is associated with veno-occlusive disease. Sub-acute veno-occlusive disease can cause vague symptoms, including colicky pains, vomiting, diarrhea, and ascites within several days; persistent liver enlargement occurs within a few weeks.

Chojkier M. Hepatic sinusoidal-obstruction syndrome: toxicity of pyrrolizidine alkaloids. J Hepatol 2003;39:437-46.
Roeder E. Medicinal plants in Europe containing pyrrolizidine alkaloids. Pharmazie 1995;50:83-98.
WHO working group. Pyrrolizidine alkaloids. Environmental Health Criteria, 80. WHO: Geneva, 1988.

Hypertension Pulmonary/Respiratory

Orally, coltsfoot might cause lung damage. The major concern with coltsfoot use is its pyrrolizidine alkaloid (PA) content. These constituents can cause lung damage with pulmonary-arterial hypertension.

Chojkier M. Hepatic sinusoidal-obstruction syndrome: toxicity of pyrrolizidine alkaloids. J Hepatol 2003;39:437-46.
Roeder E. Medicinal plants in Europe containing pyrrolizidine alkaloids. Pharmazie 1995;50:83-98.

Venous thromboembolism (VTE) Cardiovascular

Orally, a single case report associates coltsfoot and its PA content with deep vein thrombosis (DVT) and pulmonary embolus (PE). A 27-year-old man with no history of coagulation disorders developed a DVT and several PE after consuming unknown quantities of coltsfoot and several other herbs. However, he also had other risk factors for thrombosis, including smoking and recent bed rest.

Freshour JE, Odle B, Rikhye S, Stewart DW. Coltsfoot as a potential cause of deep vein thrombosis and pulmonary embolism in a patient also consuming kava and blue vervain. J Diet Suppl 2012;9:149-54.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

Dosing

There is no established, standardized dose for coltsfoot, and because of the safety concerns, no dose can be considered clearly safe. Traditional products include teas, syrups, and tinctures, but the amount of active and toxic compounds can vary widely between products.

If you choose to use coltsfoot despite the risks, only use a product certified to be free of pyrrolizidine alkaloids, follow the label directions exactly, and use it for the shortest time possible. Always check with your pharmacist or doctor first.

Pregnancy & Breastfeeding

Coltsfoot & Pregnancy

Likely Unsafe

When products containing hepatotoxic pyrrolizidine alkaloid (PA) constituents are used orally. Coltsfoot preparations containing hepatotoxic pyrrolizidine alkaloid (PA) constituents might be teratogenic and hepatotoxic. There is one case report of fatal hepatic veno-occlusive disease in a neonate associated with regular maternal consumption during pregnancy of an herb tea containing several pyrrolizidine alkaloid herbs, including coltsfoot. There is insufficient reliable information available about the safety of using coltsfoot products certified and labeled as hepatotoxic PA-free during pregnancy; avoid using.

Roulet M, Laurini R, Rivier L, Calame A. Hepatic veno-occlusive disease in newborn infant of a woman drinking herbal tea. J Pediatr 1988;112:433-6.
Chojkier M. Hepatic sinusoidal-obstruction syndrome: toxicity of pyrrolizidine alkaloids. J Hepatol 2003;39:437-46.
Roeder E. Medicinal plants in Europe containing pyrrolizidine alkaloids. Pharmazie 1995;50:83-98.

Coltsfoot & Breastfeeding

Likely Unsafe

When used orally. Hepatotoxic pyrrolizidine alkaloid (PA) constituents in coltsfoot are excreted in milk. There is insufficient reliable information available about the safety of using coltsfoot products certified and labeled as hepatotoxic PA-free during lactation; avoid using.

Chojkier M. Hepatic sinusoidal-obstruction syndrome: toxicity of pyrrolizidine alkaloids. J Hepatol 2003;39:437-46.
Roeder E. Medicinal plants in Europe containing pyrrolizidine alkaloids. Pharmazie 1995;50:83-98.

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

The 8 references that drive our Coltsfoot monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

Roulet M, Laurini R, Rivier L, Calame A. Hepatic veno-occlusive disease in newborn infant of a woman drinking herbal tea. J Pediatr 1988;112:433-6. PubMed
WHO working group. Pyrrolizidine alkaloids. Environmental Health Criteria, 80. WHO: Geneva, 1988.
Chojkier M. Hepatic sinusoidal-obstruction syndrome: toxicity of pyrrolizidine alkaloids. J Hepatol 2003;39:437-46. PubMed
Roeder E. Medicinal plants in Europe containing pyrrolizidine alkaloids. Pharmazie 1995;50:83-98.
Wilson BE, Hobbs WN. Case report: pseudoephedrine-associated thyroid storm: thyroid hormone-catecholamine interactions. Am J Med Sci 1993;306:317-9. PubMed
Wang YP, Yan J, Fu PP, Chou MW. Human liver microsomal reduction of pyrrolizidine alkaloid N-oxides to form the corresponding carcinogenic parent alkaloid. Toxicol Lett 2005;155:411-20. PubMed
Hwang SB, Chang MN, Garcia ML, et al. L-652,469--a dual receptor antagonist of platelet activating factor and dihydropyridines from Tussilago farfara L. Eur J Pharmacol 1987;141:269-81. PubMed
Freshour JE, Odle B, Rikhye S, Stewart DW. Coltsfoot as a potential cause of deep vein thrombosis and pulmonary embolism in a patient also consuming kava and blue vervain. J Diet Suppl 2012;9:149-54. PubMed

Keep reading

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

Brand directory

Brands that make products with Coltsfoot

16 brands in our database make a supplement containing Coltsfoot.

AN American Nutriceuticals 85 products Botanic Choice 253 products Energique 31 products Hawaii Pharm 4,726 products Herb Stop 193 products Herbal Terra 3,138 products Indiana Botanic Gardens 941 products Nature's Answer 1,655 products Nature's Sunshine 1,360 products New Sun 518 products Nin Jiom 1 product Plum Flower 573 products TerraVita 2,475 products TerraVita Premium Collection 4,019 products Wachters' 97 products Wise Woman Herbals 237 products

Product directory

Supplement products with Coltsfoot

60 products in our database contain Coltsfoot. Open any to see its full ingredient list and every drug interaction we check.

Pharmacist Counseling Corner

Coltsfoot: Common Questions

Does Coltsfoot interact with prescription medications?

Yes. We list 374 medications with a known interaction with Coltsfoot. Use the checker above to see how Coltsfoot interacts with a specific drug.

How are Coltsfoot interactions rated?

Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.

Is it safe to take Coltsfoot with my medications?

It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.

Where does this Coltsfoot interaction information come from?

Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.

What is Coltsfoot used for?

It has traditionally been used to soothe coughs, sore throats, and chest congestion, and to help loosen mucus. However, strong human evidence supporting these uses is lacking.

Is Coltsfoot safe to take?

It carries real safety concerns because the raw plant can contain liver-toxic pyrrolizidine alkaloids. If used at all, only choose products certified to be free of these compounds, and talk with your pharmacist or doctor first.

Can I use Coltsfoot while pregnant or breastfeeding?

No. You should avoid Coltsfoot during pregnancy and breastfeeding because its toxic alkaloids may harm your baby.

Why is Coltsfoot considered risky if it's a natural herb?

Natural does not always mean safe. Coltsfoot naturally contains pyrrolizidine alkaloids that can damage the liver, especially with repeated use.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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Products that contain Coltsfoot

A rotating sample of real supplements in our database that list Coltsfoot — open any to see its full ingredients and every drug interaction we check.

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Coltsfoot Drug Interactions, Uses, Safety & More

Your Choice:

Coltsfoot Drug Interactions: The Bottom Line

Drugs that interact with Coltsfoot

Don’t want to scroll the list? Just ask.

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Likelihood — How Well It’s Documented

Where This Data Comes From

The kinds of drugs Coltsfoot affects

Coltsfoot: Uses, Safety & Side Effects

Overview

Uses & effectiveness

How it works

Safety & precautions

Side effects

Coltsfoot: Reported Adverse Effects

Dosing

Coltsfoot & Pregnancy

Coltsfoot & Breastfeeding

References & further reading

Brands that make products with Coltsfoot

Supplement products with Coltsfoot

Coltsfoot: Common Questions

Related supplements & herbs

Products that contain Coltsfoot

Have a question about Coltsfoot?