Drug & supplement interaction

Siberian Cocklebur + Leflunomide

Leflunomide brand name: Arava.

Major Interaction
Medically reviewed by · Updated September 2026
The bottom line Major

Siberian Cocklebur has a major interaction with Leflunomide. Siberian cocklebur can adversely affect the liver.

Read the full interaction report
SeverityMajor
LikelihoodLikely
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Siberian Cocklebur and Leflunomide

Here is the interaction we found between these two, with the evidence behind it.

Major

HEPATOTOXIC DRUGS

Why this applies to Leflunomide

Leflunomide falls under HEPATOTOXIC DRUGS — the group Siberian Cocklebur interacts with.

Siberian cocklebur can adversely affect the liver. It has been linked to many cases of hepatotoxicity and some cases of liver failure. Theoretically, concomitant use with other potentially hepatotoxic drugs might increase the risk of developing liver damage. Some of these drugs include acarbose (Precose, Prandase), amiodarone (Cordarone), atorvastatin (Lipitor), azathioprine (Imuran), carbamazepine (Tegretol), cerivastatin (Baycol), diclofenac (Voltaren), felbamate (Felbatol), fenofibrate (TriCor), fluvastatin (Lescol), gemfibrozil (Lopid), isoniazid, itraconazole, (Sporanox), ketoconazole (Nizoral), leflunomide (Arava), lovastatin (Mevacor), methotrexate (Rheumatrex), nevirapine (Viramune), niacin, nitrofurantoin (Macrodantin), pioglitazone (Actos), pravastatin (Pravachol), pyrazinamide, rifampin (Rifadin), ritonavir (Norvir), rosiglitazone (Avandia), simvastatin (Zocor), tacrine (Cognex), tamoxifen, terbinafine (Lamisil), valproic acid, and zileuton (Zyflo).
Severity Major Likelihood Likely Evidence B

Well-controlled human studies have demonstrated the likely existence of this interaction.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the concern with this pairing: Siberian cocklebur can be hard on the liver on its own, and there are real-world reports of it causing liver injury and even liver failure. Leflunomide is also known to stress the liver, which is why your doctor checks your liver enzymes regularly while you're on it. Stacking two liver-stressing things together can add up and raise your risk of liver trouble.

Warning signs to watch for include yellowing of the skin or eyes, dark urine, belly pain on the upper right side, unusual tiredness, or nausea. This isn't about Leflunomide working better or worse, it's about protecting your liver. Please don't start or stop anything on your own. Talk with your pharmacist or doctor before combining these so they can weigh the risk and monitor you.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Gurley ES, Rahman M, Hossain MJ, et al. Fatal outbreak from consuming Xanthium strumarium seedlings during time of food scarcity in northeastern Bangladesh. PLoS One 2010 Mar 18;5(3):e9756. PubMed
  2. Turgut M, Alhan CC, Gurgoze M, et al. Carboxyatractyloside poisoning in humans. Ann Trop Paediatr 2005;25(2):125-34. PubMed
  3. Karabiber H, Almis H, Selimoglu MA, Yakinci C, Yilmaz S. Xanthium strumarium poisoning requiring liver transplantation. J Pediatr Gastroenterol Nutr. 2014;58(1):e6-9.

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Siberian Cocklebur Also Interacts With Other Medications

Siberian Cocklebur has 661 major, known drug interactions in our database — the Leflunomide one above is one of them. If you take anything else, check it against the full list below.

Major 661 No known interaction 2,169 (incl. Leflunomide)
Taking anything else?

Check Another of Your Medications Against Siberian Cocklebur

Covers the 2,830 medications we’ve checked against Siberian Cocklebur. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Leflunomide

This page covers Siberian Cocklebur 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), Wine (major), Ashwagandha (moderate) and Black Cohosh (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 Siberian Cocklebur as Part of a Dietary Supplement Product? Check It for Interactions

We hold 84 real supplement products containing Siberian Cocklebur, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Siberian Cocklebur. Your product may carry other ingredients that interact with Leflunomide too, on top of Siberian Cocklebur — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Siberian Cocklebur 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 Siberian Cocklebur
Top half

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

29 days ago today
Medication Leflunomide
Steady interest

#1,894 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.

Supplement

About Siberian Cocklebur

What is Siberian Cocklebur?

  • Nasal congestion and sinus problems
  • Allergic rhinitis (hay fever)
  • Headache
  • Skin conditions and itching
  • Joint and muscle discomfort

Siberian cocklebur is a fruit used in traditional Chinese and other Asian herbal medicine, mainly for nasal congestion, sinus issues, and allergies. Human evidence is very limited, and the plant contains naturally toxic compounds that can cause serious poisoning, so it should only be used under expert guidance, if at all.

Read the full Siberian Cocklebur 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.

See full Leflunomide drug information
Keep checking

Other Drugs & Siberian Cocklebur

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

661Major
0Moderate
0Minor
2,168No known interaction
661 Major 2,168 No interaction
Major

661 interactions

Showing 60 of 661 major interactions — see all 661 on the Siberian Cocklebur page.

No interaction 2,168 drugs checked — show the list

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

Showing the 60 most looked-up of 2,168 medications checked with no known interaction — see the full Siberian Cocklebur list.

See the full Siberian Cocklebur interactions page
See every supplement checked against Leflunomide, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Siberian Cocklebur monograph › Uses, safety, and every drug interaction in one place Leflunomide supplement interactions › Every supplement checked against Leflunomide, ranked by severity Leflunomide drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Siberian Cocklebur and Leflunomide Together: Common Questions

Can you take Siberian Cocklebur with Leflunomide?
This is rated a major interaction, so the combination is best avoided unless your doctor or pharmacist has specifically told you otherwise. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Siberian Cocklebur and Leflunomide interaction?
We rate it Major. This is a clinically significant combination that is generally best avoided, or used only under the direct supervision of your physician or pharmacist.

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

Still Have a Question About Leflunomide and Siberian Cocklebur?

Our pharmacists answer your medication & supplement questions — free.

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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.