Drug & supplement interaction

Schisandra + Warfarin

Warfarin brand name: Warfarin.

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

Warfarin falls into 4 drug categories that Schisandra can interact with; the most serious is rated moderate. Theoretically, schisandra might increase the levels and clinical effects of CYP2C19 substrates.

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

Schisandra and Warfarin

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

Why Are There 4 Interactions?

Schisandra interacts with whole categories of medication. Warfarin falls into 4 of those categories, so it can interact with Schisandra 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

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

Theoretically, schisandra might increase the levels and clinical effects of CYP2C19 substrates.
In vitro research shows that schisandra inhibits CYP2C19, and animal research shows that schisandra increases the concentration of voriconazole, a CYP2C19 substrate. Theoretically, schisandra may also inhibit the metabolism of other CYP2C19 substrates. This effect has not been reported in humans.
Severity Moderate 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 picture with these two together. Lab tests suggest schisandra can slow down an enzyme called CYP2C19, which is one of the pathways your body uses to clear warfarin. If that pathway slows, warfarin could build up a bit and thin your blood more than intended. With a drug like warfarin, where the dose is finely tuned, even a small shift can matter, raising the chance of bruising, nosebleeds, or more serious bleeding.

I want to be honest about the evidence: this is based on lab and animal studies, not real-world reports in people, so it's more of a theoretical concern. Still, because warfarin is so sensitive, please don't add schisandra on your own. Check with your pharmacist or doctor first, and keep up with your INR checks if you do.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Yuan F, Liang X, Chen X, Qin X, Tan C, Wang L. CYP2C19 is involved in the effect of Wuzhi tablet (Schisandra sphenanthera extract) and its constituents on the pharmacokinetics of intravenous voriconazole. Pharmazie. 2020;75(11):559-564. DOI
Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

2 of 4

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

Theoretically, schisandra might decrease the levels and clinical effects of CYP2C9 substrates.
In vitro and animal research suggests that schisandra induces CYP2C9 enzymes. This effect 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 situation with warfarin and schisandra. Your liver uses an enzyme called CYP2C9 to break warfarin down. Lab and animal studies hint that schisandra may speed that enzyme up. If that were to happen in people, your body could clear warfarin faster, leaving less of it around to thin your blood. The worry there is a weaker effect, meaning your INR could drift down and your clot risk could creep back up.

Now, the honest part: this has only been seen in test tubes and animals, never confirmed in humans, so it's theoretical. But warfarin is a narrow-margin drug where even small shifts matter. If you're thinking about schisandra, please loop in whoever manages your warfarin first so they can keep an eye on your INR.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mu Y, Zhang J, Zhang S, et al. Traditional Chinese medicines Wu Wei Zi (Schisandra chinensis Baill) and Gan Cao (Glycyrrhiza uralensis Fisch) activate pregnane X receptor and increase warfarin clearance in rats. J Pharmacol Exp Ther 2006;316:1369-77. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 4

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

Schisandra can increase the levels and clinical effects of drugs metabolized by CYP3A4.
Most clinical and laboratory research shows that schisandra, administered either as a single dose or up to twice daily for 14 days, inhibits CYP3A4 and increases the concentration of CYP3A4 substrates such as cyclophosphamide, midazolam, tacrolimus, and talinolol. Although one in vitro and animal study shows that schisandra may induce CYP3A4 metabolism, this effect appears to be overpowered by schisandra's CYP3A4 inhibitory activity and has not been reported in humans.
Severity Moderate 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 for warfarin: schisandra can slow down one of the liver enzymes (CYP3A4) that helps break warfarin down. When that enzyme is blocked, warfarin can build up a bit more than usual, which may push your blood toward being too thin. That can show up as easy bruising, nosebleeds, bleeding gums, or blood in the urine or stool.

Warfarin is a tricky drug where even small shifts in level can matter, so this isn't one to take chances with. The evidence here mostly comes from lab and animal work rather than human warfarin studies, so we can't say exactly how big the effect would be. Please don't start or stop anything on your own. Just check with your pharmacist or doctor first, and they may want to watch your INR a little more closely.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Iwata H, Tezuka Y, Kadota S, et al. Identification and characterization of potent CYP3A4 inhibitors in Schisandra fruit extract. Drug Metab Dispos 2004;32:1351-8. PubMed
  2. Mu Y, Zhang J, Zhang S, et al. Traditional Chinese medicines Wu Wei Zi (Schisandra chinensis Baill) and Gan Cao (Glycyrrhiza uralensis Fisch) activate pregnane X receptor and increase warfarin clearance in rats. J Pharmacol Exp Ther 2006;316:1369-77. PubMed
  3. Qin XL, Bi HC, Wang XD, et al. Mechanistic understanding of the different effects of Wuhzi Tablet (Schisandra sphenanthera extract) on the absorption and first-pass intestinal and hepatic metabolism of tacrolimus (FK506). Int J Pharm 2010;389:114-21.
  4. Makino, T., Mizuno, F., and Mizukami, H. Does a kampo medicine containing schisandra fruit affect pharmacokinetics of nifedipine like grapefruit juice? Biol.Pharm.Bull. 2006;29(10):2065-2069. PubMed
  5. Fan L, Mao XQ, Tao GY, Wang G, Jiang F, Chen Y, Li Q, Zhang W, Lei HP, Hu DL, Huang YF, Wang D, Zhou HH. Effect of Schisandra chinensis extract and Ginkgo biloba extract on the pharmacokinetics of talinolol in healthy volunteers. Xenobiotica. 2009 Mar;39(
  6. Jiang W, Wang X, Xu X, Kong L. Effect of Schisandra sphenanthera extract on the concentration of tacrolimus in the blood of liver transplant patients. Int J Clin Pharmacol Ther. 2010 Mar;48(3):224-9. PubMed
  7. Xin HW, Wu XC, Li Q, Yu AR, Xiong L. Effects of Schisandra sphenanthera extract on the pharmacokinetics of midazolam in healthy volunteers. Br J Clin Pharmacol. 2009 May;67(5):541-6.
  8. Li J, Chen S, Qin X, et at. Wuzhi Tablet (<i>Schisandra sphenanthera</i> Extract) is a Promising Tacrolimus-Sparing Agent for Renal Transplant Recipients Who are CYP3A5 Expressers: a Two-Phase Prospective Study. Drug Metab Dispos. 2017;45(11):1114-1119.
  9. Qin XL, Li JL, Wang SH, Chen X, Huang M, Bi HC. Co-administration of Wuzhi tablet (Schisandra sphenanthera extract) alters tacrolimus pharmacokinetics in a dose- and time-dependent manner in rats. J Ethnopharmacol. 2020;263:113233. PubMed
  10. Chen L, Ji N, Zhang M, Chen W. The influence of Wuzhi capsule on the pharmacokinetics of cyclophosphamide. Recent Pat Anticancer Drug Discov 2021. PubMed
  11. Cheng F, Li Q, Wang J, Zeng F, Zhang Y. Effects and safety evaluation of Wuzhi capsules combined with tacrolimus for the treatment of kidney transplantation recipients. J Clin Pharm Ther 2021;46(6):1636-49. PubMed
  12. Teng F, Wang W, Zhang W, et al. Effect of hepar-protecting Wuzhi capsule on pharmacokinetics and dose-effect character of tacrolimus in healthy volunteers. Biopharm Drug Dispos 2022.
  13. Kou K, Sun X, Li M, et al. Beneficial effects of Wuzhi capsule on tacrolimus blood concentrations in liver transplant patients with different donor-recipient CYP3A5 genotypes. J Clin Pharm Ther 2022;47(2):200-10. PubMed
  14. Peng Y, Jiang F, Zhou R, et al. Clinical evaluation of the efficacy and safety of co-administration of Wuzhi capsule and tacrolimus in adult Chinese patients with myasthenia gravis. Neuropsychiatr Dis Treat 2021;17:2281-9. PubMed
Moderate

WARFARIN (Coumadin)

4 of 4
Theoretically, schisandra might decrease the levels and clinical effects of warfarin.
Animal research suggests that oral schisandra extract, given daily for 6 days, reduces levels of intravenously administered warfarin. This effect might be due to the induction of cytochrome P450 (CYP) 2C9 metabolism by schisandra. However, this interaction 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 gist for warfarin. In animal studies, schisandra seems to speed up one of the liver enzymes (CYP2C9) that breaks down warfarin. If that holds true in people, your body could clear warfarin a little faster, which would make it weaker. The worry there isn't bleeding, it's the opposite: blood that clots too easily, raising your risk of a clot, stroke, or the very problem warfarin is meant to prevent.

Now, the honest part. This is only animal and lab data, and it has never been confirmed in humans. Still, warfarin is a finicky drug where even small shifts can move your INR. If you're thinking about schisandra, please loop in your pharmacist or doctor first so they can keep an eye on your INR. Don't change anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mu Y, Zhang J, Zhang S, et al. Traditional Chinese medicines Wu Wei Zi (Schisandra chinensis Baill) and Gan Cao (Glycyrrhiza uralensis Fisch) activate pregnane X receptor and increase warfarin clearance in rats. J Pharmacol Exp Ther 2006;316:1369-77. PubMed

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

Schisandra Also Interacts With Other Medications

Schisandra has 802 moderate 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.

Moderate 802 No known interaction 2,028 (incl. Warfarin)
Taking anything else?

Check Another of Your Medications Against Schisandra

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

From our Q&A

Questions About Schisandra 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 Schisandra 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 Schisandra 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 Schisandra as Part of a Dietary Supplement Product? Check It for Interactions

We hold 2,577 real supplement products containing Schisandra, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Schisandra. Your product may carry other ingredients that interact with Warfarin too, on top of Schisandra — 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 Schisandra 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 Schisandra
Top 10%

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

29 days ago today
Medication Warfarin
Top 10

#5 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 Schisandra

What is Schisandra?

Schisandra
  • Fatigue and low energy
  • Stress and adaptogen support
  • Liver health
  • Mental focus and performance
  • Menopause symptoms
  • Respiratory complaints

Schisandra is a traditional Chinese medicine berry used as an adaptogen for stress, fatigue, and liver support. Human evidence is limited and most claims are not well proven, but it appears reasonably well tolerated by most healthy adults when used short term. Pregnant and breastfeeding people should avoid it, and anyone with a health condition should check with a pharmacist or doctor first.

Read the full Schisandra 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 & Schisandra

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

0Major
802Moderate
0Minor
2,027No known interaction
802 Moderate 2,027 No interaction
Moderate

802 interactions

Showing 60 of 802 moderate interactions — see all 802 on the Schisandra page.

No interaction 2,027 drugs checked — show the list

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

Showing the 60 most looked-up of 2,027 medications checked with no known interaction — see the full Schisandra list.

See the full Schisandra 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
Schisandra 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 Schisandra and Warfarin Together: Common Questions

Can you take Schisandra with Warfarin?
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 Schisandra and Warfarin?
Warfarin belongs to more than one drug category, and Schisandra 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 Schisandra and Warfarin 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 and Schisandra?

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.