Herb & supplement monograph

Great Plantain Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Great Plantain interacts with medications. The heart of this page is the interaction list — every drug Great Plantain is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Great Plantain is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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On this page

Great Plantain Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Great Plantain drug interaction appears low for most people. Only a couple of interactions are known, none are rated major, and the concern rests on theoretical evidence rather than documented problems in people.

Interactions deserving the most attention

The one combination worth real attention involves warfarin, the blood thinner. Great plantain leaves naturally contain fairly high amounts of vitamin K, and vitamin K works against warfarin, so eating large amounts of the leaves could in theory make the medicine less effective at preventing clots. Because warfarin is a narrow-margin drug where even small changes in effect can matter, anyone taking it should treat this supplement with extra care, even though the interaction has not been confirmed in human studies.

What the rest of the list means

Great Plantain has a very short interaction list compared with many supplements. What is listed here is a predicted effect based on the plant's vitamin K content, not something shown to cause harm in people, and no interaction has been documented at the highest level of evidence.

Check your medications against Great Plantain

Based on HelloPharmacist’s Great Plantain interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Great Plantain

2 medications have a known interaction with Great Plantain, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Great Plantain using our pharmacist-reviewed interaction data.

AI summaries are generated from our Great Plantain interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction 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.
Possible. 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
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Great Plantain combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Great Plantain affects

Every type of medication (drug category) Great Plantain is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 1 drug category Great Plantain interacts with

Warfarin (coumadin)

Warfarin (Coumadin)

Theoretically, consuming large amounts of great plantain leaves, which contain vitamin K, might decrease the clinical effects of warfarin.
Great plantain leaves contain relatively high concentrations of vitamin K, which might interfere with the activity of warfarin.

Likelihood Possible Evidence D

Monograph

Great Plantain: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

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.

Scientific name: Plantago major
Family: Plantaginaceae
Part used: Leaves and seeds
Common forms: Tea, capsules, tinctures, topical salves and ointments, fresh crushed leaves (poultice)

People commonly use it for

Minor wounds and skin irritation
Insect bites and stings
Coughs and sore throat
Digestive upset
Mild inflammation

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Generally considered well tolerated for most adults, but human safety data are limited.

PregnancyLikely Unsafe

When used orally because it can increase uterine tone.

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Great Plantain (Plantago major) is a low-growing weed with broad, oval leaves and tall thin seed spikes. It grows almost everywhere, often in lawns, sidewalks, fields, and along roadsides. It is not related to the banana-like cooking plantain.

People have used the leaves and seeds of this plant for centuries in traditional and folk medicine. The fresh leaves are sometimes crushed and placed on the skin, while the dried leaves are made into teas, tinctures, or salves. The seeds and seed coats of related Plantago species (like psyllium) are well known for fiber, but Great Plantain is used mostly as a topical and respiratory remedy.

How it works

Great Plantain contains several plant compounds that may explain its traditional uses. These include aucubin (an iridoid glycoside), mucilage (a soothing, gel-like fiber), tannins, flavonoids, and allantoin.

Researchers think the mucilage may coat and soothe irritated tissue, while tannins may have a mild astringent (tightening) effect that could help minor wounds. Aucubin and flavonoids have shown anti-inflammatory and antimicrobial activity in laboratory studies. Keep in mind that these mechanisms are mostly based on lab and animal research, and how well they apply to people is not fully known.

Effectiveness

Does Great Plantain work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 9 uses evaluated

9 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

For Great Plantain, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 9 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate Burns