The short answer
Feverfew may add to bleeding concerns during heparin therapy, but the exact interaction has not been measured. The precaution is based on feverfew clotting guidance and a bleeding case without heparin.
What this answer covers
Oral Tanacetum parthenium preparations; capsule dose, extract standardization and fresh-leaf exposure are distinct.
- Supplement or preparation
- Tanacetum parthenium
- Medication ingredient
- heparin
Why the precaution exists
Federal guidance says feverfew may slow clotting. Heparin can cause serious bleeding and requires caution with agents that impair hemostasis. These sources support review of the combination without establishing how often it causes harm.
A case provides a limited clinical signal
A woman taking feverfew capsules developed prolonged vaginal bleeding and abnormal clotting tests after months of use and dose escalation. Results improved after feverfew stopped and other treatment began. She was not taking heparin, and the simultaneous treatments limit causal certainty.
Surgical timing is not dose spacing
NCCIH advises stopping feverfew at least two weeks before scheduled surgery. That should be coordinated with the surgical team; it is not a tested interval between feverfew and a heparin injection. No source establishes a safe amount for this combination.
Report symptoms and the actual product
Tell the heparin team about the exact supplement before starting or changing it. Report unusual bleeding or bruising promptly; serious bleeding, black stools or vomiting blood needs urgent assessment. Do not change prescribed heparin yourself. Include the feverfew amount, extract details and any other migraine remedies in the medication review.
Evidence and practical considerations
Side effects & toxicity
Indirect hemostatic precaution, not demonstrated exact-pair bleeding. Single feverfew case without heparin has treatment and product limitations.
- Exact scope
- Oral Tanacetum parthenium preparations; capsule dose, extract standardization and fresh-leaf exposure are distinct. with Unfractionated heparin sodium intravenous/subcutaneous, active-ingredient bridge to RxCUI5224 IN. Not LMWH or topical therapy.
- Medication form and route
- intravenous or subcutaneous unfractionated heparin; oral supplement
What remains uncertain
- No universal risk estimate, dose adjustment or spacing interval; source-specific limits apply.
Factors that may matter: Exact product; Dose/duration; Other antithrombotics; Bleeding risk; Kidney function.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People receiving parenteral unfractionated heparin.
Heparin can cause hemorrhage; medicines inhibiting platelets can add bleeding concerns. Aldosterone suppression can cause hyperkalemia, especially with predisposing conditions or potassium-sparing medicines. Heparin is not absorbed through the gastrointestinal tract.
How this applies: Exact species, preparation, route and measured endpoints govern applicability; other anticoagulants are not silently treated as heparin.
No botanical interaction specifically named. Not low-molecular-weight heparin, topical heparin cream or an oral anticoagulant; doses and risks of catheter flush products are not automatically equivalent.
Source 2: regulatory guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: Users of the specified preparation.
Feverfew may slow clotting; advises stopping at least two weeks before scheduled surgery.
How this applies: Exact species, preparation, route and measured endpoints govern applicability; other anticoagulants are not silently treated as heparin.
Not a quantified heparin interaction; presurgical guidance is not a same-day dose-spacing study.
Source 3: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 36-year-old woman with migraine.
Prolonged vaginal bleeding and abnormal PT/PTT improved after withdrawal and additional treatment.
How this applies: Exact species, preparation, route and measured endpoints govern applicability; other anticoagulants are not silently treated as heparin.
Single case with simultaneous hormonal, iron and other treatment; no rechallenge or verified standardization. Causality assessment is not proof.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Prepared exact-pair article preserving route, formulation, clinical-outcome and laboratory-endpoint distinctions. | |
| Research summary published |
Article revision: ba44c712d598a86c
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.