Drug & supplement interaction

Poison Ivy + 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 Poison Ivy 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

Poison Ivy 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 Poison Ivy 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 Poison Ivy 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.

Poison Ivy safety at a glance

Poison Ivy overall Avoid The raw plant is toxic and a potent allergen; only highly diluted homeopathic products are sold, and even these have no proven benefit.
Pregnancy Likely Unsafe When used orally or topically; avoid using. Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally or topically; avoid using. 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 Poison Ivy? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Poison Ivy 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. 4 of them are worth acting on rather than waiting out — marked below.

  • A severe skin reaction Worth acting on Additional detail

    Poison Ivy

    “Topically, poison ivy can cause contact dermatitis, reddening, swelling, and herpes-like blisters (18). These reactions occur at the area of contact, usually within a few hours, but are sometimes delayed for several days. Sometimes papules and vesicles develop and can spread beyond the area of initial contact, but are generally self-limiting and eventually form crusts..”

    Poison Ivy · Natural Medicines adverse-effect record, reported in dermatitis.

    6 sources cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    2. 68970. CASPERS, A. P. Poison ivy (Rhus toxicodendron); a survey of the poison ivy problem in Canada and some independent observations on the value of zirconium products in prophylaxis and treatment. Can.Med Assoc.J 5-15-1957;76(10):852-860.
    3. 3839. Cohen LM, Cohen JL. Erythema multiforme associated with contact dermatitis to poison ivy: three cases and a review of the literature. Cutis 1998;62:139-42.
    4. 68955. Lee, N. P. and Arriola, E. R. Poison ivy, oak, and sumac dermatitis. West J.Med. 1999;171(5-6):354-355.
    5. 68960. Kurlan, J. G. and Lucky, A. W. Black spot poison ivy: A report of 5 cases and a review of the literature. J.Am.Acad.Dermatol. 2001;45(2):246-249. PubMed
    6. 68977. Cardinali, C., Francalanci, S., Giomi, B., Caproni, M., Sertoli, A., and Fabbri, P. Contact dermatitis from Rhus toxicodendron in a homeopathic remedy. J Am Acad.Dermatol. 2004;50(1):150-151. PubMed

    Leflunomide

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

  • Shortness of breath / A higher chance of infection Worth acting on Additional detail

    Poison Ivy

    “Inhaled, urushiol in the smoke from burning of poison ivy can result in life-threatening throat swelling, fever, and secondary lung infections (6). Respiratory distress syndrome after smoke inhalation from burning poison ivy has also been reported. Two fatal cases of acute respiratory distress and anaphylaxis after inhaling burned poison ivy are reported in patients with known allergies to poison ivy.”

    Poison Ivy · Natural Medicines adverse-effect record, reported in acute respiratory distress syndrome (ards).

    3 sources cited
    1. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
    2. 69036. Kollef, M. H. Adult respiratory distress syndrome after smoke inhalation from burning poison ivy. JAMA 7-26-1995;274(4):358-359. DOI
    3. 112420. Woolery S, Willner J, Prahlow JA, Douglas E. Death After Poison Ivy Smoke Inhalation. Am J Forensic Med Pathol 2022;43(4):359-362. PubMed

    Leflunomide

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

  • A severe allergic reaction Worth acting on Additional detail

    Poison Ivy

    Recorded for Poison Ivy in the same Natural Medicines adverse-effect record shown under Shortness of breath / A higher chance of infection above.

    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

    Poison Ivy

    Recorded for Poison Ivy in the same Natural Medicines adverse-effect record shown under A severe skin reaction above.

    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 ›

  • Dizziness Additional detail

    Poison Ivy

    “Orally, poison ivy can cause dizziness, fever, stupor, and unconsciousness (18).”

    Poison Ivy · Natural Medicines adverse-effect record, reported in vertigo.

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    Leflunomide

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

  • Diarrhea / Vomiting / Nausea Additional detail

    Poison Ivy

    “Orally, poison ivy can cause severe mucous membrane irritation, nausea, vomiting, and diarrhea (18).”

    Poison Ivy · Natural Medicines adverse-effect record, reported in diarrhea.

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    Leflunomide

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

Reported for Poison Ivy but not commonly for Leflunomide: kidney problems, swelling and fever.

Effects for Leflunomide come from the ADVERSE REACTIONS section of its FDA label; effects for Poison Ivy 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

Poison Ivy in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Unsafe

When used orally or topically; 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 Poison Ivy 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 Poison Ivy as Part of a Dietary Supplement Product? Check It for Interactions

We hold 3 real supplement products containing Poison Ivy, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Poison Ivy. Even though Poison Ivy 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 Poison Ivy 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 Poison Ivy
Steady interest

#1,337 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Leflunomide
Steady interest

#1,863 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 Poison Ivy reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Poison Ivy 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 Poison Ivy

What is Poison Ivy?

  • Joint pain and stiffness
  • Muscle soreness or strains
  • Skin rashes and itching
  • Arthritis discomfort
  • Restlessness with body aches

Poison ivy is a toxic plant best known for causing an itchy, blistering allergic rash on contact. In supplement form it is sold almost exclusively as an extremely dilute homeopathic remedy (Rhus tox) for joint and muscle pain, but reliable evidence that it works is lacking, and the raw plant should never be used or ingested.

Toxicodendron radicans · Anacardiaceae · Leaves, stems, and root (used in highly diluted homeopathic preparations); fresh plant in traditional use · Homeopathic pellets, tablets, and topical preparations (sold as 'Rhus tox' or 'Rhus toxicodendron')

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

Poison Ivy: dosing

There is no established, science-based dose for poison ivy. The raw plant has no safe oral or topical dose and should never be used.Homeopathic Rhus tox is sold in various "potencies" (such as 6C or 30C) and forms, including pellets and tablets.

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

Read the full Poison Ivy 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 & Poison Ivy

Browse every other medication we’ve checked against Poison Ivy — 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 Poison Ivy 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 Poison Ivy list.

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

Poison Ivy References

The 21 references that drive our Poison Ivy 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. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Cohen LM, Cohen JL. Erythema multiforme associated with contact dermatitis to poison ivy: three cases and a review of the literature. Cutis 1998;62:139-42.
  4. Lee, N. P. and Arriola, E. R. Poison ivy, oak, and sumac dermatitis. West J.Med. 1999;171(5-6):354-355.
  5. Kurlan, J. G. and Lucky, A. W. Black spot poison ivy: A report of 5 cases and a review of the literature. J.Am.Acad.Dermatol. 2001;45(2):246-249. PubMed
  6. CASPERS, A. P. Poison ivy (Rhus toxicodendron); a survey of the poison ivy problem in Canada and some independent observations on the value of zirconium products in prophylaxis and treatment. Can.Med Assoc.J 5-15-1957;76(10):852-860.
  7. Cardinali, C., Francalanci, S., Giomi, B., Caproni, M., Sertoli, A., and Fabbri, P. Contact dermatitis from Rhus toxicodendron in a homeopathic remedy. J Am Acad.Dermatol. 2004;50(1):150-151. PubMed
  8. Werchniak, A. E. and Schwarzenberger, K. Poison ivy: an underreported cause of erythema multiforme. J Am Acad.Dermatol. 2004;51(5 Suppl):S159-S160. PubMed
  9. Schram, S. E., Willey, A., Lee, P. K., Bohjanen, K. A., and Warshaw, E. M. Black-spot poison ivy. Dermatitis 2008;19(1):48-51. DOI
  10. Resnick, S. D. Poison-ivy and poison-oak dermatitis. Clin.Dermatol. 1986;4(2):208-212. PubMed
  11. Baer, R. L. Poison ivy dermatitis. Cutis 1986;37(6):434-436.
  12. Hurwitz, R. M., Rivera, H. P., and Guin, J. D. Black-spot poison ivy dermatitis. An acute irritant contact dermatitis superimposed upon an allergic contact dermatitis. Am.J.Dermatopathol. 1984;6(4):319-322. PubMed
  13. Schwartz, R. S. and Downham, T. F. Erythema multiforme associated with Rhus contact dermatitis. Cutis 1981;27(1):85-86.
  14. Mallory, S. B., Miller, O. F., III, and Tyler, W. B. Toxicodendron radicans dermatitis with black lacquer deposit on the skin. J.Am.Acad.Dermatol. 1982;6(3):363-368. PubMed
  15. Kollef, M. H. Adult respiratory distress syndrome after smoke inhalation from burning poison ivy. JAMA 7-26-1995;274(4):358-359. DOI

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 Poison Ivy and Leflunomide Together: Common Questions

Is it safe to take Poison Ivy with Leflunomide?
We do not list a known interaction between Poison Ivy 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 Poison Ivy and Leflunomide have any of the same side effects?
Yes — our sources link each of them separately to 9 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 — Poison Ivy 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

Poison Ivy 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 21 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Leflunomide and Poison Ivy?

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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.