Herb & supplement monograph

Butterbur Drug Interactions, Uses, Effectiveness, Safety & More

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

What is this page for?

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

But these pages have grown well beyond that into a full monograph — what Butterbur 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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Reviewed by licensed pharmacists Sourced from Natural Medicines

On this page

Butterbur 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 Butterbur drug interaction appears low for most people. None of the listed interactions are rated major, and every one of them traces back to a single theoretical concern that has not been confirmed in human studies.

Interactions deserving the most attention

The medications that deserve the most attention are CYP3A4 inducers, drugs that speed up an enzyme the body uses to process certain substances. Some butterbur products contain natural compounds called pyrrolizidine alkaloids, and in theory these enzyme-boosting drugs could convert those compounds into forms that are harder on the liver. This concern applies to butterbur products that still contain these alkaloids, and it rests on lab-based reasoning rather than reported harm in people.

What the rest of the list means

Although the number of listed medications is fairly large, they all reflect this one predicted mechanism rather than dozens of separate proven problems. In other words, the long list comes from how the interaction was modeled, not from real-world reports of harm, and no interaction here has been demonstrated in well-controlled human studies.

Check your medications against Butterbur

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

Interaction report

Drugs that interact with Butterbur

87 medications have a known interaction with Butterbur, 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 Butterbur using our pharmacist-reviewed interaction data.

AI summaries are generated from our Butterbur 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 Butterbur 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 Butterbur affects

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

All 1 drug category Butterbur interacts with

Cytochrome P450 3a4 (cyp3a4) Inducers

Cytochrome P450 3A4 (Cyp3A4) Inducers

Theoretically, CYP3A4 inducers might increase the toxicity of butterbur.
The pyrrolizidine alkaloid (PA) constituents found in some butterbur products are substrates of CYP3A4. Theoretically, drugs that induce CYP3A4 might increase the conversion of PAs to toxic metabolites.

Likelihood Possible Evidence D

Monograph

Butterbur: Uses, Safety & Side Effects

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

The bottom line

Butterbur is a plant extract most studied for preventing migraines and easing hay fever symptoms, and some standardized products show promise. However, raw or unprocessed butterbur contains compounds that can seriously harm the liver, so only use PA-free (pyrrolizidine alkaloid-free) products, and avoid it during pregnancy and breastfeeding. Talk to your pharmacist or doctor before trying it.

Scientific name: Petasites hybridus
Family: Asteraceae
Part used: Roots (rhizome) and leaves
Common forms: Capsules, tablets, standardized extracts, tinctures

People commonly use it for

Migraine prevention
Hay fever (allergic rhinitis)
Asthma symptoms
Stomach and digestive upset
Tension headaches

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

Safety at a glance

OverallUse caution

Only PA-free standardized products should be used because raw butterbur can damage the liver.

PregnancyLikely Unsafe

When butterbur preparations containing pyrrolizidine alkaloid (PA) constituents are used orally. These constituents might be teratogenic and hepatotox...

Read the full pregnancy detail

BreastfeedingLikely Unsafe

When butterbur preparations containing pyrrolizidine alkaloid (PA) constituents are used orally. PAs are excreted in breast milk. There is insufficien...

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

Butterbur (Petasites hybridus) is a shrub-like plant that grows in wet, marshy areas across Europe, Asia, and parts of North America. It has very large leaves, and its name comes from the old practice of using those leaves to wrap butter in warm weather.

The roots and leaves have been used in traditional medicine for hundreds of years. Today, people most often take butterbur as a capsule or tablet made from a standardized extract. It is most popular for preventing migraine headaches and for easing seasonal allergy symptoms.

Raw butterbur naturally contains chemicals called pyrrolizidine alkaloids (PAs), which can harm the liver. Because of this, reputable supplements are processed to remove these compounds and are labeled "PA-free."

How it works

Butterbur contains active compounds called petasin and isopetasin. Laboratory and animal research suggests these may relax smooth muscle and reduce inflammation.

For migraines, researchers think butterbur may help calm blood vessel spasms and lower inflammatory signals in the brain. For allergies, it may reduce the body's release of histamine and leukotrienes, which are chemicals that trigger sneezing, congestion, and a runny nose.

Keep in mind that much of this understanding comes from lab and animal studies, so the exact way it works in people is not fully proven.

Effectiveness

Does Butterbur work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 10 uses evaluated

2 Possibly effective 1 Leans ineffective 7 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

Possibly Effective Allergic rhinitis (hay fever)