The short answer
Ask your prescriber before adding willow bark to mefenamate. Medicinal willow guidance advises medical review with NSAIDs, but the exact added bleeding risk and a protective spacing interval are unknown.
What this answer covers
Oral willow bark products with oral mefenamic acid 250 mg capsules. Medicinal Salix bark guidance has defined preparation scope; exact species and salicin content must be checked.
- Supplement or preparation
- Willow Bark
- Medication ingredient
- mefenamate
The monograph calls for medical advice
The final European medicinal willow bark monograph advises against combining its covered preparations with salicylates or other NSAIDs without medical advice. oral mefenamic acid 250 mg capsules is an NSAID, so this is a relevant reason for review, while the exact combination’s bleeding risk remains unmeasured.
The species and product still matter
Willow bark products vary in Salix species, extract and salicin content. Show the pharmacist the full label rather than assuming all willow products are interchangeable or equivalent to aspirin.
Consider your stomach and bleeding history
The willow monograph contraindicates use with active peptic ulcer and NSAID hypersensitivity. The prescription medicine also carries GI warnings. Tell your clinician about past ulcers, bleeding, aspirin reactions and other pain relievers before adding a botanical product for pain.
Do not rely on a few hours of separation
No established spacing interval has been shown to prevent the potential overlapping effects. Ask for a pain-management plan that accounts for the exact preparation and your history. Seek urgent care for vomiting blood or black, tarry stools, and report persistent stomach discomfort promptly.
Evidence and practical considerations
Side effects & toxicity
An exact increase in bleeding or GI injury from willow bark with mefenamate has not been measured.
- Exact scope
- Oral willow bark products with oral mefenamic acid 250 mg capsules. Medicinal Salix bark guidance has defined preparation scope; exact species and salicin content must be checked. with Exact mefenamate IN 257844 linked by current RxNorm to mefenamic acid PIN 6693. The inspected oral acid capsules supply the explicit ingredient bridge, not meclofenamate or a different fenamate.
- Medication form and route
- Oral
What remains uncertain
- Regulatory NSAID co-use warning is precautionary. Unspecified willow bark products may differ from the defined medicinal preparations.
Factors that may matter: Exact preparation and dose; Fasting versus fed dosing; Bleeding and ulcer history; Other medicines.
Read the supporting source summaries
Source 1: Current prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Prescription oral oral mefenamic acid 250 mg capsules users; short human pharmacology studies where described.
Short-term acute pain up to seven days and primary dysmenorrhea indications. Serious GI warnings; magnesium hydroxide raises peak concentration and AUC in a small human study.
How this applies: Exact current product label. Exact mefenamate IN 257844 linked by current RxNorm to mefenamic acid PIN 6693. The inspected oral acid capsules supply the explicit ingredient bridge, not meclofenamate or a different fenamate.
Exact oral product label; no measured botanical co-use incidence. Ingredient, route, preparation and comparator differences must be retained.
Source 2: Final regulatory herbal monograph
ema.europa.eu · Source check Sep 10, 2026
Population: Users of defined Salix bark preparations.
Advises against concomitant salicylates or other NSAIDs without medical advice; active ulcer and NSAID hypersensitivity are contraindications.
How this applies: Precaution for medicinal willow products; exact S. alba applicability remains limited by botanical identification.
No exact pair bleeding estimate. Defined medicinal species/preparations cannot authenticate unspecified products. Salix alba is not specifically named among the principal listed species.
Source 3: Medication terminology
rxnav.nlm.nih.gov · Source check Sep 10, 2026
Population: Terminology.
mefenamate is IN. Exact mefenamate IN 257844 linked by current RxNorm to mefenamic acid PIN 6693. The inspected oral acid capsules supply the explicit ingredient bridge, not meclofenamate or a different fenamate.
How this applies: Exact identity.
Not clinical evidence.
Research assessment: · Open full citations ↗
Side effects & toxicity
Medicinal willow bark should not be added to an NSAID without medical advice.
- Exact scope
- Oral willow bark products with oral mefenamic acid 250 mg capsules. Medicinal Salix bark guidance has defined preparation scope; exact species and salicin content must be checked. with Exact mefenamate IN 257844 linked by current RxNorm to mefenamic acid PIN 6693. The inspected oral acid capsules supply the explicit ingredient bridge, not meclofenamate or a different fenamate.
- Medication form and route
- Oral
What remains uncertain
- Supported for defined medicinal willow products; not a measured exact-species combination risk, universal salicin dose or validated timing solution.
Factors that may matter: Exact preparation and dose; Fasting versus fed dosing; Bleeding and ulcer history; Other medicines.
Read the supporting source summaries
Source 1: Current prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Prescription oral oral mefenamic acid 250 mg capsules users; short human pharmacology studies where described.
Short-term acute pain up to seven days and primary dysmenorrhea indications. Serious GI warnings; magnesium hydroxide raises peak concentration and AUC in a small human study.
How this applies: Exact current product label. Exact mefenamate IN 257844 linked by current RxNorm to mefenamic acid PIN 6693. The inspected oral acid capsules supply the explicit ingredient bridge, not meclofenamate or a different fenamate.
Exact oral product label; no measured botanical co-use incidence. Ingredient, route, preparation and comparator differences must be retained.
Source 2: Final regulatory herbal monograph
ema.europa.eu · Source check Sep 10, 2026
Population: Users of defined Salix bark preparations.
Advises against concomitant salicylates or other NSAIDs without medical advice; active ulcer and NSAID hypersensitivity are contraindications.
How this applies: Precaution for medicinal willow products; exact S. alba applicability remains limited by botanical identification.
No exact pair bleeding estimate. Defined medicinal species/preparations cannot authenticate unspecified products. Salix alba is not specifically named among the principal listed species.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Sources checked and article drafted. | |
| Research summary published |
Article revision: 220f3d9b639c73e6
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.