Reviewed records available

Butterbur

Petasites hybridus

A named processed root extract showed a dose-specific migraine-prevention signal in one randomized trial. That result cannot be separated from butterbur's central safety boundary: the raw plant can contain toxic pyrrolizidine alkaloids.

Evidence snapshot reviewed October 16, 2026

Check the botanical identity in the Plant Atlas →

Botanical identity

Which plant this profile means

This profile is tied to Petasites hybridus and keeps a named processed root extract categorically separate from raw plant material, tea, leaf products, and unverified supplements.

Scientific name
Petasites hybridus
WCVP taxon ID
2912815
Atlas record
Open this name in the Plant Atlas

Preparation boundaries

Same plant, different exposure

These forms stay separate in the evidence bank. A result for one cannot be copied onto the others.

Standardized extract

rhizome or root · Taken by mouth

The migraine trial studied a named processed root extract. Its abstract does not itself establish pyrrolizidine-alkaloid control, and the result cannot transfer to raw butterbur, tea, leaf material, or an arbitrary retail product.

unverified preparation

varied plant material · Route varies

Raw or unverified butterbur can contain toxic pyrrolizidine alkaloids and is categorically separate from a studied processed extract.

Research-bot status

Some evidence cards are public. The rest of the queue isn’t.

The reviewed cards below cleared a separate publication check. The remaining candidate extractions stay private until their source, wording, and preparation match are reviewed.

Sources in review
2
Possible claims found
3
Still awaiting review
0
Blocked source
0

Research connections

What this ingredient has been studied around

Migraine prevention

A reviewed, preparation-specific evidence card is published for this source.

Liver safety

A reviewed, preparation-specific evidence card is published for this source.

Reviewed evidence

2 source-linked records

Randomized trial Promising, with limits 245 adults with two to six migraine attacks per month

A named butterbur root extract for migraine: dose-specific efficacy, unresolved safety transfer

The higher-dose extract arm reduced migraine frequency more than placebo in the trial's per-protocol analysis. The lower-dose arm did not beat placebo on the primary endpoints. Those dose-specific results apply to the named processed root extract, and the abstract does not by itself establish that the product was free of toxic pyrrolizidine alkaloids.

What was studied
A named standardized special Petasites hybridus root extract; not raw butterbur, tea, leaf material, or an arbitrary supplement
Setting
Studied alone
Why it ranks here
A randomized trial found a positive result for one extract arm and a null result for the lower arm, but the analysis and later butterbur safety concerns prevent broad transfer to the plant or retail products.
Limits and cautions
  • The reported efficacy result was from a per-protocol analysis.
  • The 75 mg twice-daily arm and 50 mg twice-daily arm had different results and must not be collapsed into a generic butterbur effect.
  • The PubMed abstract does not itself establish pyrrolizidine-alkaloid control.
  • The result cannot be transferred to raw plant material, tea, leaf products, or an arbitrary supplement.
  • The most common possibly related adverse effects in the trial were mild gastrointestinal events, mainly burping; this does not settle uncommon or liver-related risk.

Raw or PA-containing butterbur can be dangerous. Even a product represented as PA-free needs credible quality verification, and reported liver injury remains relevant. This card is not a recommendation to use butterbur for migraine prevention.

Evidence synthesis Safety and tolerability only Plant chemistry and processing review, not a clinical trial

Butterbur's preparation boundary: the raw plant can contain toxic alkaloids

Butterbur is a good example of why a plant name is not enough. The raw plant can contain toxic pyrrolizidine alkaloids, so a clinical result for a processed extract cannot be transferred to tea, raw root, leaf material, or an unverified supplement. This review describes the chemistry and processing boundary; it is not a clinical safety trial and does not certify a retail product.

What was studied
Raw butterbur plant material and the analytical processing needed to produce pyrrolizidine-alkaloid-controlled extracts
Setting
Not an efficacy study
Why it ranks here
The source establishes a chemically important preparation boundary: direct plant use can carry toxic alkaloid exposure, while controlled extraction requires deliberate raw-material selection and analytical verification.
Limits and cautions
  • This is an analytical and physiological review, not a comparative clinical safety trial.
  • It does not estimate how often human liver injury occurs.
  • It does not certify any current retail product as PA-free.
  • A label claim is not the same as independent testing and quality control.
  • The review establishes a preparation boundary, not a dose recommendation.

Do not use raw or unverified butterbur. Products represented as PA-free still require trustworthy quality verification, and butterbur should not be used in pregnancy, breastfeeding, or for children without qualified medical guidance.

Profile sources

Read the source material