Drug & supplement interaction

Kudzu + Phenytoin

Phenytoin brand names: Dilantin Kapseals, Dilantin, Di-Phen, Dilantin Infatabs, Phenytek, and others.

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

Kudzu has a moderate interaction with Phenytoin. Theoretically, concomitant use might have additive hepatotoxic effects.

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

Kudzu and Phenytoin

Here is the interaction we found between these two, with the evidence behind it.

Moderate

HEPATOTOXIC DRUGS

Why this applies to Phenytoin

Phenytoin falls under HEPATOTOXIC DRUGS — the group Kudzu interacts with.

Theoretically, concomitant use might have additive hepatotoxic effects.
There is some concern that kudzu can adversely affect the liver.
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: both phenytoin (Dilantin) and kudzu can be hard on the liver, and the worry is that using them together might add up to extra strain. Phenytoin can occasionally cause liver problems on its own, and kudzu has raised some similar concerns. So in theory, stacking them could increase that risk.

I want to be honest, though: this is a theoretical caution based on how each affects the liver, not strong real-world proof. It does not change how well your phenytoin controls seizures. Still, phenytoin needs careful blood levels, so don't add kudzu without checking first. If you notice yellowing skin or eyes, dark urine, belly pain, or unusual tiredness, call your doctor. Talk with your pharmacist before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Kim HJ, Kim H, Ahn JH, Suk JH. Liver injury induced by herbal extracts containing mistletoe and kudzu. J Altern Complement Med 2015;21(3):180-5. PubMed
  2. Santosh N, Mohan K, Royana S, Yamini TB. Hepatotoxicity of tubers of Indian Kudzu (Pueraria tuberosa) in rats. Food Chem Toxicol. 2010 Apr;48(4):1066-71. PubMed
  3. Teschke R, Zhang L, Long H, Schwarzenboeck A, Schmidt-Taenzer W, Genthner A, Wolff A, Frenzel C, Schulze J, Eickhoff A. Traditional Chinese Medicine and herbal hepatotoxicity: a tabular compilation of reported cases. Ann Hepatol. 2015 Jan-Feb;14(1):7-19. DOI
  4. Wang D, Qiu L, Wu X, Wei H, Xu F. Evaluation of kudzu root extract-induced hepatotoxicity. J Ethnopharmacol. 2015 Dec 24;176:321-6. 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

Kudzu Also Interacts With Other Medications

Kudzu has 511 moderate, 72 minor known drug interactions in our database — the Phenytoin one above is one of them. If you take anything else, check it against the full list below.

Moderate 511 Minor 72 No known interaction 2,247 (incl. Phenytoin)
Taking anything else?

Check Another of Your Medications Against Kudzu

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

From our Q&A

Questions About Kudzu or Phenytoin

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

This page covers Kudzu only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phenytoin page lists 224 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Kava (major).

By severity: 9 major · 187 moderate · 28 minor.

From our pharmacist’s overview on the Phenytoin page

“Phenytoin (Dilantin) is a seizure medicine with a narrow therapeutic index, meaning small changes in its blood level can bring seizures back or tip over into toxicity, so I treat its supplement list with real seriousness. The biggest group, 78 ingredients, piles on sedation, and alcohol, kava, and GHB all rate major for exactly that re…”

Reviewed by 2 · Jul 18, 2026

Open the Phenytoin interaction page

One more smart check

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

We hold 536 real supplement products containing Kudzu, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Kudzu. Your product may carry other ingredients that interact with Phenytoin too, on top of Kudzu — 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 Kudzu and Phenytoin 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 Kudzu
Top 25%

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

29 days ago today
Medication Phenytoin
Top half

#820 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 Kudzu

What is Kudzu?

Kudzu
  • Alcohol cravings and reduction
  • Menopausal symptoms
  • Heart and blood vessel health
  • Hangover relief
  • Traditional Chinese medicine (Ge Gen)

Kudzu is a fast-growing vine whose root has long been used in traditional Chinese medicine and is now studied mostly for reducing alcohol intake. Early research is promising for cutting back on drinking, but evidence for most other uses is weak. Talk with your pharmacist or doctor before trying it, and avoid it during pregnancy and breastfeeding.

Read the full Kudzu monograph & all interactions
Medication

About Phenytoin

What Is Phenytoin Used For?

Brand names: Dilantin Kapseals, Dilantin, Di-Phen, Dilantin Infatabs, Phenytek, Dilantin injection

Phenytoin treats seizures. Oral products are used for generalized tonic-clonic (grand mal) seizures and for psychomotor (temporal lobe) or complex partial seizures. Most oral products are also used to prevent and treat seizures during or after neurosurgery.

Phenytoin Sodium Injection is used for generalized tonic-clonic status epilepticus (a prolonged, dangerous seizure emergency). It is also used for seizures during neurosurgery. The injection should be used only when taking phenytoin by mouth is not possible. Dilantin-125 and Phenytoin oral suspension are listed for tonic-clonic and psychomotor seizures.

See full Phenytoin drug information
Keep checking

Other Drugs & Kudzu

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

0Major
511Moderate
72Minor
2,246No known interaction
511 Moderate 72 Minor 2,246 No interaction
Moderate

511 interactions

Showing 60 of 511 moderate interactions — see all 511 on the Kudzu page.

Minor

72 interactions

Showing 60 of 72 minor interactions — see all 72 on the Kudzu page.

No interaction 2,246 drugs checked — show the list

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

Showing the 60 most looked-up of 2,246 medications checked with no known interaction — see the full Kudzu list.

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

Can you take Kudzu with Phenytoin?
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.
How serious is the Kudzu and Phenytoin 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 Phenytoin and Kudzu?

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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.