Drug & supplement interaction

Goji + Warfarin

Warfarin brand name: Warfarin.

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

Warfarin falls into 4 drug categories that Goji can interact with; the most serious is rated major. Goji can increase the effects of warfarin and possibly increase the risk of bleeding.

Read the full interaction report
SeverityMajor
LikelihoodProbable
Interactions4
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Goji and Warfarin

These two interact in 4 distinct ways. Each one is explained separately below.

Why Are There 4 Interactions?

Goji interacts with whole categories of medication. Warfarin falls into 4 of those categories, so it can interact with Goji in 4 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Major).

Major

WARFARIN (Coumadin)

1 of 4
Goji can increase the effects of warfarin and possibly increase the risk of bleeding.
There are at least 5 case reports of increased international normalized ratio (INR) in patients stabilized on warfarin who began drinking goji juice, concentrated goji tea, or goji wine. Goji may inhibit the metabolism of warfarin by cytochrome P450 2C9 (CYP2C9).
Severity Major Likelihood Probable Evidence D

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..

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

Here's the gist with warfarin and goji: your liver uses an enzyme called CYP2C9 to clear warfarin out of your system. Goji appears to slow that enzyme down, so warfarin can build up and thin your blood more than your dose intends. There are a handful of real-world reports of people whose INR jumped after they started drinking goji juice, strong goji tea, or goji wine while on a steady warfarin dose.

Practically, that means a higher chance of bleeding, things like easy bruising, nosebleeds, bleeding gums, or blood in the urine or stool. Warfarin is a narrow-window drug, so even small shifts matter. The evidence here is mostly case reports, but the signal is consistent enough that I'd loop in your pharmacist or doctor before adding concentrated goji, and don't stop or change anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Lam AY, Elmer GW, Mohutsky MA. Possible interaction between warfarin and Lycium Barbarum. Ann Pharmacother 2001;35:1199-201.
  2. Leung H, Hung A, Hui AC, Chan TY. Warfarin overdose due to the possible effects of Lycium barbarum L. Food Chem Toxicol 2008;46:1860-2. PubMed
  3. Rivera, C. A., Ferro, C. L., Bursua, A. J., and Gerber, B. S. Probable interaction between Lycium barbarum (goji) and warfarin. Pharmacotherapy 2012;32(3):e50-e53.
  4. Guzmán CE, Guzmán-Moreno CG, Assad-Morell JL, Edgar Francisco Carrizales-Sepúlveda EF. Flecainide toxicity associated with the use of goji berries: a case report. Eur Heart J Case Rep. 2021;5(6):ytab204. PubMed
  5. Zhang J, Tian L, Xie B. Bleeding due to a probable interaction between warfarin and Gouqizi (Lycium Barbarum L.). Toxicol Rep. 2015;2:1209-1212. PubMed
Moderate

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES

2 of 4

Why this applies to Warfarin

Warfarin falls under CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES — the group Goji interacts with.

Theoretically, goji berry might inhibit CYP2C19 and reduce metabolism of CYP2C19 substrates.
In vitro research shows that goji berry tincture and juice inhibit CYP2C19 enzymes. Concomitant use with goji may decrease metabolism and increase levels of CYP2C19 substrates. However, this has not been reported in humans.
Severity Moderate Likelihood Possible Evidence D

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.

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

Here's the simple version: warfarin is partly cleared by a liver enzyme called CYP2C19. In test-tube studies, goji berry seems to slow that enzyme down. In theory, if your body breaks warfarin down more slowly, a bit more could hang around, which could nudge your blood toward being too thin. With warfarin that matters, because it has a narrow safety window. Signs to watch would be easy bruising, nosebleeds, bleeding gums, or blood in your urine or stool.

That said, this is theory only, based on lab work and never confirmed in real people, so don't panic. Still, because warfarin is so dose-sensitive, please tell your pharmacist or doctor before adding concentrated goji supplements, and keep up with your regular INR checks.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Liu R, Tam TW, Mao J, et al. In vitro activity of Lycium barbarum (Goji) against major human phase I metabolism enzymes. Complement Integr Med. 2016;13(3):257-265.
Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

3 of 4

Warfarin also falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES.

Theoretically, goji berry might inhibit CYP2C9 and reduce metabolism of CYP2C9 substrates.
In vitro research shows that goji berry tincture and juice inhibit CYP2C9 enzymes. Additionally, multiple case reports suggest that goji berry concentrated tea and juice inhibit the metabolism of warfarin, a CYP2C9 substrate. Concomitant use with goji may decrease metabolism and increase levels of CYP2C9 substrates.
Severity Moderate Likelihood Possible Evidence D

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.

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

Here's the deal with goji and warfarin. Your body clears warfarin using an enzyme called CYP2C9. Goji berry, especially as concentrated juice or strong tea, appears to slow that enzyme down. When warfarin isn't cleared as fast, it can build up and thin your blood more than intended. That raises your risk of bleeding, things like easy bruising, nosebleeds, bleeding gums, or blood in your urine or stool.

Warfarin is a narrow-therapeutic-index drug, so even small shifts can nudge your INR up. The evidence here is limited (mostly lab studies and a few case reports), and an occasional handful of berries likely isn't the worry. Concentrated goji products are the concern. Please check with your pharmacist or doctor before adding them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Lam AY, Elmer GW, Mohutsky MA. Possible interaction between warfarin and Lycium Barbarum. Ann Pharmacother 2001;35:1199-201.
  2. Guzmán CE, Guzmán-Moreno CG, Assad-Morell JL, Edgar Francisco Carrizales-Sepúlveda EF. Flecainide toxicity associated with the use of goji berries: a case report. Eur Heart J Case Rep. 2021;5(6):ytab204. PubMed
  3. Liu R, Tam TW, Mao J, et al. In vitro activity of Lycium barbarum (Goji) against major human phase I metabolism enzymes. Complement Integr Med. 2016;13(3):257-265.
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

4 of 4

Warfarin also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, goji berry might inhibit CYP3A4 and reduce metabolism of CYP3A4 substrates.
In vitro research shows that goji berry juice inhibits CYP3A4 enzymes. Concomitant use with goji may decrease metabolism and increase levels of CYP3A4 substrates. However, this has not been reported in humans.
Severity Moderate Likelihood Possible Evidence D

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.

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

Here's the short version for goji and warfarin. In lab dish studies, goji juice seemed to slow down an enzyme called CYP3A4, which is one of the pathways your body uses to clear warfarin. If that enzyme is slowed, warfarin could build up a bit and thin your blood more than expected. With warfarin, that may show up as easy bruising, bleeding gums, nosebleeds, or a higher INR on your blood test.

I want to be honest, though: this has only been seen in the lab, not in real people. But because warfarin is a narrow-margin drug where small shifts matter, I'd play it safe. Eating an occasional goji berry is unlikely to be an issue, but before starting a concentrated goji supplement, check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Liu R, Tam TW, Mao J, et al. In vitro activity of Lycium barbarum (Goji) against major human phase I metabolism enzymes. Complement Integr Med. 2016;13(3):257-265.

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

Goji Also Interacts With Other Medications

Goji has 1 major, 930 moderate, 68 minor known drug interactions in our database — the Warfarin one above is among them. If you take anything else, check it against the full list below.

Major 1 Moderate 930 Minor 68 No known interaction 1,831 (incl. Warfarin)
Taking anything else?

Check Another of Your Medications Against Goji

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

From our Q&A

Questions About Goji 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 Goji 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:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Warfarin

This page covers Goji 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

Open the Warfarin interaction page

One more smart check

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

We hold 1,738 real supplement products containing Goji, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Goji. Your product may carry other ingredients that interact with Warfarin too, on top of Goji — 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 Goji 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.

Supplement Goji
Top 10%

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

29 days ago today
Medication Warfarin
Top 10

#4 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 Goji

What is Goji?

Goji
  • General antioxidant support
  • Eye health
  • Immune support
  • Anti-aging and well-being
  • Blood sugar support

Goji berries are a nutritious fruit rich in antioxidants, vitamins, and plant polysaccharides, and they are safe for most people as a food. While they are popular for eye health, immune support, and general wellness, strong human evidence for most health claims is limited. Talk with your pharmacist or doctor before using concentrated goji supplements, especially if you take medications or are pregnant.

Read the full Goji monograph & all interactions
Medication

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.

See full Warfarin drug information
Keep checking

Other Drugs & Goji

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

1Major
930Moderate
68Minor
1,830No known interaction
1 Major 930 Moderate 68 Minor 1,830 No interaction
Major

1 interaction

Moderate

930 interactions

Showing 60 of 930 moderate interactions — see all 930 on the Goji page.

Minor

68 interactions

Showing 60 of 68 minor interactions — see all 68 on the Goji page.

No interaction 1,830 drugs checked — show the list

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

Showing the 60 most looked-up of 1,830 medications checked with no known interaction — see the full Goji list.

See the full Goji interactions page
See every supplement checked against Warfarin, 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
Goji monograph › Uses, safety, and every drug interaction in one place Warfarin supplement interactions › Every supplement checked against Warfarin, ranked by severity Warfarin 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 Goji and Warfarin Together: Common Questions

Can you take Goji with Warfarin?
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.
Why are there 4 interactions listed for Goji and Warfarin?
Warfarin belongs to more than one drug category, and Goji interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Goji and Warfarin 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 Warfarin and Goji?

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.