Drug & supplement interaction

Rooibos + Warfarin Sodium

Warfarin Sodium brand names: Coumadin, Panwarfin, Sofarin.

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

Warfarin Sodium falls into 4 drug categories that Rooibos can interact with; the most serious is rated moderate. Theoretically, taking rooibos with CYP2C19 substrates may increase the effects of CYP2C19 substrates.

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

Rooibos and Warfarin Sodium

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

Why Are There 4 Interactions?

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

Moderate

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES

1 of 4

Why this applies to Warfarin Sodium

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

Theoretically, taking rooibos with CYP2C19 substrates may increase the effects of CYP2C19 substrates.
In vitro research shows that the methanol extract of rooibos leaves and stems strongly inhibits CYP2C19 enzyme activity.
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 gist for warfarin. Your body uses several liver enzymes to clear this blood thinner, and one of them is called CYP2C19. Lab studies (done in test tubes, not in people) suggest that concentrated rooibos may slow that enzyme down. In theory, that could let a little more warfarin linger in your system, nudging its blood-thinning effect higher and raising the chance of bruising or bleeding.

I want to be honest though: this is theoretical and based only on lab data, so we don't know if a cup or two of rooibos tea would do anything at all. Since warfarin is a narrow-margin drug where even small shifts show up on your INR, just let your doctor or pharmacist know if you start drinking rooibos regularly or use any concentrated extract.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Fantoukh OI, Dale OR, Parveen A, et al. Safety Assessment of Phytochemicals Derived from the Globalized South African Rooibos Tea (Aspalathus linearis) through Interaction with CYP, PXR, and P-gp. J Agric Food Chem. 2019;67(17):4967-4975.
Moderate

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

2 of 4

Warfarin Sodium also falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES.

Theoretically, taking rooibos with CYP1A2 substrates may increase the effects of CYP1A2 substrates.
In vitro research shows that the methanol extract of rooibos leaves and stems inhibits CYP1A2 enzyme activity.
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 gist for warfarin and rooibos. Some lab (test tube) studies hint that rooibos may slow down a liver enzyme called CYP1A2, which is one of the enzymes that helps clear warfarin from your body. In theory, if that enzyme works slower, a bit more warfarin could stick around, which might nudge your blood-thinning effect higher and raise the chance of bruising, nosebleeds, or other bleeding.

I want to be honest though: this is only seen in lab studies, not in real people, so it's far from proven. Still, warfarin is a tricky drug where even small shifts matter, and your INR is the number to watch. Enjoying a cup of rooibos tea now and then is likely fine, but check with your pharmacist or doctor before using concentrated rooibos extracts, and keep your INR checks on schedule.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Fantoukh OI, Dale OR, Parveen A, et al. Safety Assessment of Phytochemicals Derived from the Globalized South African Rooibos Tea (Aspalathus linearis) through Interaction with CYP, PXR, and P-gp. J Agric Food Chem. 2019;67(17):4967-4975.
Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

3 of 4

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

Theoretically, taking rooibos with CYP2C9 substrates may increase the effects of CYP2C9 substrates.
In vitro research shows that the methanol extract of rooibos leaves and stems inhibits CYP2C9 enzyme activity.
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 gist for warfarin drinkers: your liver uses an enzyme called CYP2C9 to break warfarin down and clear it out. Lab studies suggest rooibos extract can slow that enzyme a bit. In theory, that means warfarin could hang around longer and your blood could end up thinner than intended. With a drug as finicky as warfarin, where small shifts in your INR matter a lot, that could show up as easy bruising, nosebleeds, or bleeding that's hard to stop.

Now, I want to be honest about the evidence. This is based only on test-tube research, not real people, so it's far from proven. A cup or two of rooibos tea probably won't rock the boat, but concentrated extracts are another story. Before adding either, please loop in your pharmacist or doctor so your INR stays steady.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Fantoukh OI, Dale OR, Parveen A, et al. Safety Assessment of Phytochemicals Derived from the Globalized South African Rooibos Tea (Aspalathus linearis) through Interaction with CYP, PXR, and P-gp. J Agric Food Chem. 2019;67(17):4967-4975.
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

4 of 4

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

Theoretically, taking rooibos with CYP3A4 substrates may increase the effects of CYP3A4 substrates.
In vitro research shows that the methanol extract of rooibos leaves and stems strongly inhibits CYP3A4 enzyme activity.
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 gist with warfarin and rooibos. Your liver uses an enzyme called CYP3A4 to help clear warfarin out of your body. In test-tube studies (not people), concentrated rooibos extract slowed that enzyme down. In theory, if warfarin breaks down more slowly, more of it could linger and thin your blood a little too much. With a drug like warfarin, where the dose is finely tuned, even small shifts can matter and could mean easy bruising, nosebleeds, or bleeding that's harder to stop.

The good news: this is weak, lab-only evidence, and a cup or two of rooibos tea is unlikely to cause trouble. I'd still mention it to your pharmacist or doctor, especially before using strong rooibos extracts, and keep up your regular INR checks.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Fantoukh OI, Dale OR, Parveen A, et al. Safety Assessment of Phytochemicals Derived from the Globalized South African Rooibos Tea (Aspalathus linearis) through Interaction with CYP, PXR, and P-gp. J Agric Food Chem. 2019;67(17):4967-4975.

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

Rooibos Also Interacts With Other Medications

Rooibos has 878 moderate known drug interactions in our database — the Warfarin Sodium one above is among them. If you take anything else, check it against the full list below.

Moderate 878 No known interaction 1,952 (incl. Warfarin Sodium)
Taking anything else?

Check Another of Your Medications Against Rooibos

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

From our Q&A

Questions About Rooibos or Warfarin Sodium

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Rooibos or Warfarin Sodium, 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 Sodium

This page covers Rooibos only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Warfarin Sodium 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).

Open the Warfarin Sodium interaction page

One more smart check

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

We hold 142 real supplement products containing Rooibos, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Rooibos. Your product may carry other ingredients that interact with Warfarin Sodium too, on top of Rooibos — 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 Rooibos and Warfarin Sodium 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 Rooibos
Top half

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

29 days ago today
Medication Warfarin Sodium
Top 1%

#18 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 Rooibos

What is Rooibos?

Rooibos
  • Caffeine-free beverage
  • Antioxidant support
  • Heart health
  • Blood sugar support
  • Digestive upset
  • General wellness

Rooibos is a caffeine-free herbal tea from South Africa that is rich in antioxidants and generally considered safe as a beverage. While lab and early studies suggest possible benefits for heart health, blood sugar, and inflammation, strong human evidence is lacking for most medical uses. Enjoy it as a tea, but talk to your pharmacist or doctor before using concentrated extracts for health reasons.

Read the full Rooibos monograph & all interactions
Medication

About Warfarin

What Is Warfarin Used For?

Brand names: Coumadin, Panwarfin, Sofarin

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 & Rooibos

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

0Major
878Moderate
0Minor
1,951No known interaction
878 Moderate 1,951 No interaction
Moderate

878 interactions

Showing 60 of 878 moderate interactions — see all 878 on the Rooibos page.

No interaction 1,951 drugs checked — show the list

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

Showing the 60 most looked-up of 1,951 medications checked with no known interaction — see the full Rooibos list.

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

Can you take Rooibos with Warfarin Sodium?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 4 interactions listed for Rooibos and Warfarin Sodium?
Warfarin Sodium belongs to more than one drug category, and Rooibos 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 Rooibos and Warfarin Sodium interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About Warfarin Sodium and Rooibos?

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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.