Drug & supplement interaction

English Walnut + Leflunomide

Leflunomide brand name: Arava.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between English Walnut and Leflunomide in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

English Walnut and Leflunomide

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Leflunomide and English Walnut in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

Worth understanding: our licensed dataset holds no drug-interaction record for English Walnut at all — not against Leflunomide, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

English Walnut safety at a glance

English Walnut overall Use caution Walnuts are generally safe as food but can cause serious allergic reactions in people with tree nut allergies.
Pregnancy Likely Safe When the fruit (nut), leaf, or hull is consumed in amounts normally found in foods. Read the full pregnancy detail
Breastfeeding Likely Safe When the fruit (nut), leaf, or hull is consumed in amounts normally found in foods. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Leflunomide and English Walnut? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests English Walnut and Leflunomide May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

  • A severe allergic reaction Worth acting on Additional detail

    English Walnut

    “Orally, the fruit (nut) of English walnut is well tolerated; however, it can cause softening of stools and mild bloating. Oral allergy syndrome may occur in people who are allergic to English walnuts. This is characterized by itching of the oral cavity immediately after consumption. Rarely this syndrome may cause swelling of the lips and tongue (angioedema).”

    English Walnut · Natural Medicines adverse-effect record, reported in allergic rhinitis (hay fever).

    6 sources cited
    1. 8476. Chisholm A, Mann J, Skeaff M, et al. A diet rich in walnuts favourably influences plasma fatty acid profile in moderately hyperlipidaemic subjects. Eur J Clin Nutr 1998;52:12-6. PubMed
    2. 8477. Sabate J, Fraser GE, Burke K, et al. Effects of walnuts on serum lipid levels and blood pressure in normal men. N Engl J Med 1993;328:603-7. PubMed
    3. 6431. Zambon D, Sabate J, Munoz S, et al. Substituting walnuts for monounsaturated fat improves the serum lipid profile of hypercholesterolemic men and women. A randomized crossover trial. Ann Intern Med 2000;132:538-46. PubMed
    4. 8479. Asero R. Detection and clinical characterization of patients with oral allergy syndrome caused by stable allergens in Rosaceae and nuts. Ann Allergy Asthma Immunol 1999;83:377-83. PubMed
    5. 97750. Hosseini S, Jamshidi L, Mehrzadi S, et al. Effects of Juglans regia L. leaf extract on hyperglycemia and lipid profiles in type two diabetic patients: a randomized double-blind, placebo-controlled clinical trial. J Ethnopharmacol. 2014;152(3):451-6. PubMed
    6. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.

    “Tree nuts, which include English walnuts, can cause allergic reactions in sensitive individuals. Due to the prevalence of this allergy in the general population, tree nuts are classified as a major food allergen in the United States.

    Oral allergy syndrome may occur in people who are allergic to English walnuts. This is characterized by itching of the oral cavity immediately after consumption.”

    English Walnut · Natural Medicines adverse-effect record, reported in allergic rhinitis (hay fever).

    2 sources cited
    1. 105410. Food and Drug Administration. Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA); Public Law 108-282, Title II. Accessed on May 19, 2021. Available at: https://www.fda.gov/food/food-allergensgluten-free-guidance-documents-regulatory-infor
    2. 8479. Asero R. Detection and clinical characterization of patients with oral allergy syndrome caused by stable allergens in Rosaceae and nuts. Ann Allergy Asthma Immunol 1999;83:377-83. PubMed

    Leflunomide

    Listed in the ADVERSE REACTIONS section of the FDA label for Leflunomide. Read the label on DailyMed ›

  • An allergic reaction Worth acting on Additional detail

    English Walnut

    Recorded for English Walnut in the same Natural Medicines adverse-effect record shown under A severe allergic reaction above.

    Leflunomide

    Listed in the ADVERSE REACTIONS section of the FDA label for Leflunomide. Read the label on DailyMed ›

  • Bloating or gas / Diarrhea Additional detail

    English Walnut

    “Orally, the fruit (nut) of English walnut might cause softening of stools and mild bloating. Oral allergy syndrome may occur in people who are allergic to English walnuts. This is characterized by itching of the oral cavity immediately after consumption. Rarely this syndrome may cause swelling of the lips and tongue (angioedema).”

    English Walnut · Natural Medicines adverse-effect record, reported in allergic rhinitis (hay fever).

    5 sources cited
    1. 6431. Zambon D, Sabate J, Munoz S, et al. Substituting walnuts for monounsaturated fat improves the serum lipid profile of hypercholesterolemic men and women. A randomized crossover trial. Ann Intern Med 2000;132:538-46. PubMed
    2. 8479. Asero R. Detection and clinical characterization of patients with oral allergy syndrome caused by stable allergens in Rosaceae and nuts. Ann Allergy Asthma Immunol 1999;83:377-83. PubMed
    3. 97750. Hosseini S, Jamshidi L, Mehrzadi S, et al. Effects of Juglans regia L. leaf extract on hyperglycemia and lipid profiles in type two diabetic patients: a randomized double-blind, placebo-controlled clinical trial. J Ethnopharmacol. 2014;152(3):451-6. PubMed
    4. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
    5. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.

    Leflunomide

    Listed in the ADVERSE REACTIONS section of the FDA label for Leflunomide. Read the label on DailyMed ›

  • A skin rash reported in 13.2% of FDA reports for Leflunomide Additional detail

    English Walnut

    “Topically, English walnut hull preparations, which contain juglone, can cause a temporary yellow or brown discoloration of skin and mucous membranes. It can also cause contact dermatitis (12,12980).”

    English Walnut · Natural Medicines adverse-effect record, reported in dermatitis.

    2 sources cited
    1. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
    2. 12980. Bonamonte D, Foti C, Angelini G. Hyperpigmentation and contact dermatitis due to Juglans regia. Contact Dermatitis 2001;44:101-2. PubMed

    Leflunomide

    Listed in the ADVERSE REACTIONS section of the FDA label for Leflunomide, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Itching Additional detail

    English Walnut

    Recorded for English Walnut in the same Natural Medicines adverse-effect record shown under A severe allergic reaction above.

    Leflunomide

    Listed in the ADVERSE REACTIONS section of the FDA label for Leflunomide. Read the label on DailyMed ›

Reported for English Walnut but not commonly for Leflunomide: swelling.

Effects for Leflunomide come from the ADVERSE REACTIONS section of its FDA label; effects for English Walnut come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 104,033 voluntary FDA FAERS reports for Leflunomide that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

English Walnut in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Safe

When the fruit (nut), leaf, or hull is consumed in amounts normally found in foods.

Pregnancy And Lactation Possibly Unsafe

When the bark is used orally or topically; avoid using. There is insufficient reliable information available about the safety of the fruit, leaf, or hull when used orally in medicinal amounts during pregnancy and lactation; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Everything else you take

See Every Supplement That Interacts With Leflunomide

This page covers English Walnut only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Leflunomide page lists 59 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Siberian Cocklebur (major), Wine (major) and Ashwagandha (moderate).

By severity: 4 major · 46 moderate · 9 minor.

From our pharmacist’s overview on the Leflunomide page

“Leflunomide (Arava) quiets rheumatoid arthritis by damping down the immune system, and its best-known danger is liver injury, so the 59 supplements and herbs on this page are worth slowing down for. Thirty-eight of them carry liver risks of their own, and of the four rated major, two are simply alcoholic drinks, while a third, Siberian…”

Reviewed by 2 · Jul 18, 2026

Open the Leflunomide interaction page

One more smart check

Taking English Walnut as Part of a Dietary Supplement Product? Check It for Interactions

We hold 34 real supplement products containing English Walnut, each one broken down to its full ingredient list — and combination products often carry several ingredients besides English Walnut. Even though English Walnut itself has no known interaction with Leflunomide, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where English Walnut and Leflunomide Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement English Walnut
Steady interest

#1,240 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Leflunomide
Steady interest

#1,505 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every English Walnut reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The English Walnut and Leflunomide records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About English Walnut

What is English Walnut?

  • Heart and cholesterol health
  • Brain health
  • General nutrition (omega-3 source)
  • Antioxidant support
  • Traditional skin and digestive remedies (leaf/husk)

English walnut is a nutritious tree nut rich in plant-based omega-3 fats, fiber, and antioxidants, and eating it as part of a balanced diet may support heart health. Most concentrated supplement or leaf-extract uses have limited human evidence. If you have a tree nut allergy, avoid it, and check with your pharmacist before using supplements.

Juglans regia · Juglandaceae · Nuts (kernels), leaves, and the green husks; sometimes the bark · Whole nuts, walnut oil, capsules or softgels, leaf tea or extract

An interaction check asks whether these two react with each other — it does not ask whether English Walnut is a good idea for someone in your situation. Here is what our English Walnut record says about it on its own.

English Walnut: dosing

There is no official standardized medicinal dose for English walnut. As a food, a small handful of walnuts is a common everyday serving and fits into most healthy diets.For capsules, walnut oil, or leaf extracts, a proven therapeutic dose has not been established.

From our English Walnut monograph — the full record covers uses, side effects and every documented interaction.

Read the full English Walnut monograph & all interactions
Medication

About Leflunomide

What Is Leflunomide Used For?

Brand name: Arava

Leflunomide tablets — sold under the brand name Arava and as generic leflunomide — are used to treat active rheumatoid arthritis (RA) in adults. Both Arava and generic leflunomide tablets are FDA-approved for this use.

Rheumatoid arthritis is an autoimmune condition in which the immune system attacks the joints, causing pain, swelling, and stiffness. Leflunomide helps calm that overactive immune response to reduce symptoms and slow joint damage.

Most-Reported Side Effects for Leflunomide

From FAERS, the FDA’s public side-effect reporting system (104,033 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Rheumatoid arthritis 25,337 reports
Arthralgia 17,395 reports
Drug intolerance 15,935 reports
Joint swelling 15,925 reports
Fatigue 15,756 reports
See full Leflunomide drug information
Keep checking

Other Drugs & English Walnut

Browse every other medication we’ve checked against English Walnut — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

We also checked English Walnut against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full English Walnut list.

See the full English Walnut interactions page
See every supplement checked against Leflunomide, ranked by severity
Evidence & sources

English Walnut References

The 16 references that drive our English Walnut monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
  2. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  3. Electronic Code of Federal Regulations. Title 21. Part 182 -- Substances Generally Recognized As Safe. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=182
  4. Zambon D, Sabate J, Munoz S, et al. Substituting walnuts for monounsaturated fat improves the serum lipid profile of hypercholesterolemic men and women. A randomized crossover trial. Ann Intern Med 2000;132:538-46. PubMed
  5. Chisholm A, Mann J, Skeaff M, et al. A diet rich in walnuts favourably influences plasma fatty acid profile in moderately hyperlipidaemic subjects. Eur J Clin Nutr 1998;52:12-6. PubMed
  6. Sabate J, Fraser GE, Burke K, et al. Effects of walnuts on serum lipid levels and blood pressure in normal men. N Engl J Med 1993;328:603-7. PubMed
  7. Feldman EB. The scientific evidence for a beneficial health relationship between walnuts and coronary heart disease. J Nutr 2002;132:1062S-101S. PubMed
  8. Asero R. Detection and clinical characterization of patients with oral allergy syndrome caused by stable allergens in Rosaceae and nuts. Ann Allergy Asthma Immunol 1999;83:377-83. PubMed
  9. Bonamonte D, Foti C, Angelini G. Hyperpigmentation and contact dermatitis due to Juglans regia. Contact Dermatitis 2001;44:101-2. PubMed
  10. Hu FB, Stampfer MJ. Nut consumption and risk of coronary heart disease: a review of epidemiologic evidence. Curr Atheroscler Rep 1999;1:204-9. PubMed
  11. Tapsell LC, Gillen LJ, Patch CS, et al. Including walnuts in a low-fat/modified-fat diet improves HDL cholesterol-to-total cholesterol ratios in patients with type 2 diabetes. Diabetes Care 2004;27:2777-83. PubMed
  12. Rabiei K, Ebrahimzadeh MA, Saeedi M, et al. Effects of a hydroalcoholic extract of Juglans regia (walnut) leaves on blood glucose and major cardiovascular risk factors in type 2 diabetic patients: a double-blind, placebo-controlled clinical trial. BMC Com PubMed
  13. Hosseini S, Jamshidi L, Mehrzadi S, et al. Effects of Juglans regia L. leaf extract on hyperglycemia and lipid profiles in type two diabetic patients: a randomized double-blind, placebo-controlled clinical trial. J Ethnopharmacol. 2014;152(3):451-6. PubMed
  14. FDA. Qualified Health Claims: Letter of Enforcement Discretion - Walnuts and Coronary Heart Disease (Docket No 02P-0292). March 2004. Available at: http://wayback.archive-it.org/7993/20171114183649/https:/www.fda.gov/Food/IngredientsPackagingLabeling/Labe
  15. Food and Drug Administration. Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA); Public Law 108-282, Title II. Accessed on May 19, 2021. Available at: https://www.fda.gov/food/food-allergensgluten-free-guidance-documents-regulatory-infor

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking English Walnut and Leflunomide Together: Common Questions

Is it safe to take English Walnut with Leflunomide?
We do not list a known interaction between English Walnut and Leflunomide. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do English Walnut and Leflunomide have any of the same side effects?
Yes — our sources link each of them separately to 6 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Does Leflunomide interact with any supplements?
Yes. Leflunomide has documented interactions with 59 supplements in our database — English Walnut is not one of them. The Leflunomide interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

English Walnut monograph Uses, safety profile, and every drug interaction in one place Leflunomide drug information The full plain-English guide to this medication Leflunomide supplement interactions Every supplement checked against Leflunomide, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 16 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Leflunomide and English Walnut?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.