The short answer
No reliable spacing rule or universal avoidance requirement has been established for feverfew with aspirin. Feverfew can affect coagulation measurements, and a bleeding case has been reported without aspirin. These findings justify reviewing the combination with a clinician, while leaving the exact added risk uncertain.
What this answer covers
Oral Tanacetum parthenium, feverfew, with oral aspirin. Powdered above-ground herb, the capsule products used in studies and concentrated extracts are distinct preparations. Evidence for purified parthenolide or other Tanacetum species is not treated as equivalent.
- Supplement or preparation
- Tanacetum parthenium
- Medication ingredient
- aspirin
What does the newer human trial tell us?
A 2022 trial assigned healthy men to feverfew 250 mg daily or placebo for two weeks. One clotting measurement, prothrombin time, was slightly longer with feverfew. Aspirin was mentioned in the paper’s background but was not given as a study treatment. The result therefore does not measure an aspirin interaction or prove that feverfew can replace aspirin.
What happened in the bleeding case?
A woman using feverfew capsules for migraine developed prolonged vaginal bleeding and abnormal clotting tests after months of use and a dose increase. Results improved after feverfew was stopped and other treatment was given. She was not taking aspirin in the report, and the treatment changes make the feverfew contribution difficult to isolate.
Do platelet experiments prove the combination is harmful?
Laboratory feverfew extracts inhibited several platelet responses, but these experiments did not give feverfew and aspirin together to patients. They help explain a possible concern rather than its clinical size. The adopted European monograph records no reported interactions for its specified powdered-herb preparation; that statement is not a controlled demonstration of safety.
What is a reasonable plan for taking both?
Ask your pharmacist or prescriber to review the exact capsule or extract, daily amount and reason for aspirin treatment. No proven number of hours between them was identified. A clinician can decide whether avoiding an optional supplement is appropriate for your bleeding history and other medicines. Do not use feverfew as a substitute for prescribed aspirin.
What should I report while using these products?
Report unusual or prolonged bleeding, including substantial changes in menstrual bleeding. Aspirin’s label identifies vomiting blood, black or bloody stools and faintness as warning signs requiring medical attention. Give the clinician the dates of supplement starts and dose changes so that other causes and medicines can also be assessed.
Evidence and practical considerations
Timing & monitoring
No reliable spacing rule or universal avoidance requirement has been established for feverfew with aspirin. Feverfew can affect coagulation measurements, and a bleeding case has been reported without aspirin. These findings justify reviewing the combination with a clinician, while leaving the exact added risk uncertain.
- Exact scope
- Oral Tanacetum parthenium, feverfew, with oral aspirin. Powdered above-ground herb, the capsule products used in studies and concentrated extracts are distinct preparations. Evidence for purified parthenolide or other Tanacetum species is not treated as equivalent. with Aspirin, RxCUI 1191, IN, oral use. The inspected 81 mg enteric-coated tablet label names aspirin as its active ingredient and basis of strength; studies using oral 80, 325 or 500 mg are described individually. These strengths and release forms do not establish equivalent interaction magnitude. Other salicylates, salicylate salts and non-aspirin antiplatelet medicines are not treated as the exact drug.
- Medication form and route
- oral
- Timing or duration
- Limited to each source’s stated exposure; no untested duration or spacing interval is inferred.
What remains uncertain
- No inspected human aspirin-feverfew coadministration study establishes clinical bleeding or a management interval. Feverfew-only findings and laboratory mechanisms are indirect; monograph silence is not evidence of safety.
Factors that may matter: feverfew preparation and dose; duration and changes in use; aspirin indication; other medicines; bleeding history.
Read the supporting source summaries
Source 1: regulatory OTC drug label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Users of oral aspirin 81 mg enteric-coated tablets.
Warns of severe stomach bleeding and identifies faintness, vomiting blood and bloody or black stools as reasons to seek medical attention. Directs patients to consult a doctor before use with prior ulcers or bleeding problems.
How this applies: Exact aspirin identity and baseline safety context; not direct proof for an individual botanical pair.
Does not identify a measured interaction with garlic, ginkgo or feverfew. Intrinsic aspirin bleeding risk is not proof of an added botanical effect, and an 81 mg coated product is not the same regimen as every cited study.
Source 2: primary randomized placebo-controlled human study
sciencedirect.com · Source check Sep 10, 2026
Population: 60 healthy nonsmoking adult men randomized; the public results preview reports 57 completing the study.
Prothrombin time was 12.2 versus 11.6 seconds with feverfew and control, respectively (P=0.003 unadjusted; P=0.04 regression). The preview distinguishes other within-group changes from the between-group finding.
How this applies: Supports a possible effect on coagulation under the studied preparation, not a clinical aspirin separation/avoidance rule.
Abstract/public-preview access only. Detailed capsule standardization and complete analyses not verified. Clotting-test changes are surrogate findings, not demonstrated clinical bleeding or aspirin interaction; no preventive efficacy or aspirin replacement claim follows.
Source 3: primary clinical case report
journalmc.org · Source check Sep 10, 2026
Population: A 36-year-old woman with migraine and prolonged vaginal bleeding.
Bleeding and abnormal PT/PTT were reported. Four months after feverfew withdrawal plus medroxyprogesterone, iron and other treatment, hemoglobin and coagulation results improved; the authors rated the feverfew adverse reaction probable.
How this applies: A feverfew safety signal warranting caution, without transferring it to a demonstrated exact aspirin interaction or an onset/spacing rule.
One case, simultaneous treatment, no rechallenge and unresolved product standardization. The abstract compresses the dose history; the body provides escalation. A causality score is not proof and no aspirin interaction was tested.
Source 4: primary laboratory experiment
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Laboratory blood-platelet and polymorphonuclear leukocyte experiments, not a clinical coadministration trial.
Extracts inhibited platelet secretion and aggregation under several experimental conditions, while thromboxane synthesis was not inhibited.
How this applies: Mechanistic plausibility only; cannot supply a dose, clinical effect size or validated management rule for the exact pair.
Abstract only, no aspirin-treated patients, clinical bleeding outcome or oral timing experiment. The mechanism differs from a simple assumption that feverfew is a botanical aspirin.
Source 5: official regulatory herbal monograph
ema.europa.eu · Source check Sep 10, 2026
Population: Adults using dried powdered above-ground parts as an oral traditional herbal medicine.
The adopted monograph records no reported interactions in section 4.5 and supplies no aspirin separation interval.
How this applies: Preserves preparation limits and contrary regulatory context without treating silence as refutation of an interaction.
Absence of reported interactions is not proof of safety. The document predates the subsequently published coagulation trial and does not test aspirin co-use. A 2026 revision consultation is listed, but no replacement adopted monograph was identified.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Original sources checked and a new article prepared, preserving direct co-use evidence, contrary findings and formulation limits. No independent clinical review is recorded. | |
| Research summary published |
Article revision: 5af6d23b3c80dc21
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.