Great Plantain + Warfarin
Warfarin brand name: Warfarin.
Great Plantain has a moderate interaction with Warfarin. Theoretically, consuming large amounts of great plantain leaves, which contain vitamin K, might decrease the clinical effects of warfarin.
Read the full interaction reportGreat Plantain and Warfarin
Here is the interaction we found between these two, with the evidence behind it.
WARFARIN (Coumadin)
Great plantain leaves contain relatively high concentrations of vitamin K, which might interfere with the activity of warfarin.
Interaction 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.
Here's the thing to know if you take warfarin: this medicine works by blocking vitamin K, which your body needs to form clots. Great plantain leaves happen to contain a fair amount of vitamin K, so in theory, eating large quantities could push back against your warfarin and make it work less well. That could leave you at higher risk for the very clots warfarin is meant to prevent.
I'll be honest, this is a theoretical concern based on the plant's vitamin K content, not something proven in studies. A cup of soothing tea now and then is unlikely to rock the boat. But because warfarin is so finicky (your INR can swing from small changes), keep your intake steady and let your pharmacist or doctor know before you start using it regularly.
- Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
- Adom MB, Taher M, Mutalabisin MF, et al. Chemical constituents and medical benefits of Plantago major. Biomed Pharmacother. 2017;96:348-360. PubMed
What These Ratings Mean
Every interaction above is graded three ways — here’s the key to each label.
Clinically significant. Avoid the combination, or use only under close professional supervision.
Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.
Generally not serious. Be aware of it and mention it to your pharmacist.
- 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.
- 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.
Great Plantain Also Interacts With Other Medications
Great Plantain has 1 moderate known drug interaction in our database — the Warfarin one above is one of them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Great Plantain
We haven’t checked that one against Great Plantain yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Great Plantain. Pick one to open its full report.
Questions About Great Plantain or Warfarin
These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Great Plantain or Warfarin, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:
- Does Ginger Water Interfere With Amoxicillin-Clavulanate? ›
- Can You Take Nattokinase With a 40 mg Statin? ›
- Is Krill Oil Safe To Take With Losartan? ›
Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.
See Every Supplement That Interacts With Warfarin
This page covers Great Plantain only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Warfarin page lists 361 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: Activated Charcoal (major), Alfalfa (major), American Ginseng (major), Beer (major) and Cannabis (major).
By severity: 16 major · 301 moderate · 44 minor.
From our pharmacist’s overview on the Warfarin page
“People take warfarin to prevent dangerous clots, and many are the same people reaching for glucosamine for sore joints or a multivitamin containing vitamin K, which makes this a list that deserves genuine respect. Of the 361 supplements on file for warfarin, 16 carry a major rating, and the danger runs in both directions: some add to w…”
Reviewed by 2 · Jul 18, 2026
Where Great Plantain and Warfarin 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.
#1,082 of 1,452 supplements looked up here in the last 7 days
#4 of 2,830 medications looked up here in the last 7 days
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.
About Great Plantain
What is Great Plantain?
- Minor wounds and skin irritation
- Insect bites and stings
- Coughs and sore throat
- Digestive upset
- Mild inflammation
Great Plantain is a common weed traditionally used on the skin for minor wounds and bites, and as a tea for coughs or stomach upset. Human evidence for most of these uses is limited, though the plant appears generally well tolerated. Talk with your pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or have a health condition.
About Warfarin
What Is Warfarin Used For?
Brand name: Warfarin
Warfarin sodium tablets and Jantoven tablets are both used to prevent and treat venous thrombosis (blood clots in the veins) and pulmonary embolism (a clot in the lungs). They are also used to prevent clot-related complications in people with atrial fibrillation (an irregular heart rhythm) or who have had a heart valve replaced.
In people who have had a heart attack, warfarin is used to reduce the risk of death, another heart attack, stroke, or other clotting events. It does not dissolve an existing clot, but it helps prevent the clot from growing and stops new dangerous clots from forming.
Other Drugs & Great Plantain
Browse every other medication we’ve checked against Great Plantain — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
1 interaction
No interaction 2,828 drugs checked — show the list
We also checked Great Plantain against these medications and found no known interaction in our sources. Open any page to confirm.
- Apixaban ›
- Levothyroxine ›
- Amlodipine ›
- Methylphenidate ›
- Sertraline ›
- Testosterone ›
- Losartan Potassium ›
- Metoprolol ›
- Ivermectin ›
- Aspirin ›
- Rivaroxaban ›
- Rosuvastatin ›
- Escitalopram ›
- Acetaminophen ›
- Tadalafil ›
- Clopidogrel ›
- Atorvastatin ›
- Docusate ›
- Valacyclovir ›
- Hydroxyurea ›
- Abemaciclib ›
- Methamphetamine ›
- Ibuprofen ›
- Sumatriptan ›
- Semaglutide ›
- Tirzepatide ›
- Prednisone ›
- Propranolol ›
- Bupropion ›
- Lisdexamfetamine ›
- Metformin ›
- Amoxicillin ›
- Acyclovir ›
- Lisinopril ›
- Bendamustine ›
- Amitriptyline ›
- Doxycycline ›
- Methotrexate ›
- Fluoxetine ›
- Lamotrigine ›
- Amphetamine ›
- Gabapentin ›
- Pregabalin ›
- Acetaminophen, Codeine ›
- Azithromycin ›
- Dextroamphetamine ›
- Isotretinoin ›
- Clonazepam ›
- Omeprazole ›
- Quetiapine ›
- Methylene Blue ›
- Amlodipine Besylate ›
- Duloxetine ›
- Letrozole ›
- Buspirone ›
- Citalopram ›
- Naproxen ›
- Ciprofloxacin ›
- Bisoprolol ›
- Levothyroxine, Liothyronine ›
Showing the 60 most looked-up of 2,828 medications checked with no known interaction — see the full Great Plantain list.
Sources & How We Checked
Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for vitamins, herbs and supplements — the basis for our interaction data.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for the medication overviews.
- NIH Dietary Supplement Label Database (DSLD) — Official supplement product labels.
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
Taking Great Plantain and Warfarin Together: Common Questions
Can you take Great Plantain with Warfarin?
How serious is the Great Plantain and Warfarin interaction?
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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.