Drug & supplement interaction

Noni + 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

Phenytoin falls into 2 drug categories that Noni can interact with; the most serious is rated moderate. Theoretically, taking noni with hepatotoxic drugs might increase the risk of liver damage.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Noni and Phenytoin

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Noni interacts with whole categories of medication. Phenytoin falls into 2 of those categories, so it can interact with Noni in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

HEPATOTOXIC DRUGS

1 of 2

Why this applies to Phenytoin

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

Theoretically, taking noni with hepatotoxic drugs might increase the risk of liver damage.
There is concern that noni might cause hepatotoxicity in some patients. Advise patients against combining noni with potentially hepatotoxic drugs.
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: both noni and phenytoin can, in rare cases, be hard on your liver. Phenytoin already carries a known (though uncommon) risk of liver irritation, and noni has been linked to a handful of liver injury reports too. Stacking two things that lean on the liver in the same direction is the worry here, not phenytoin building up or wearing off.

I'll be honest, this concern is mostly theoretical and based on scattered case reports, not strong studies. Still, since phenytoin needs careful balancing anyway, I wouldn't add concentrated noni juice or capsules on your own. Watch for yellowing skin or eyes, dark urine, belly pain, or unusual tiredness, and check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Millonig G, Stadlmann S, Vogel W. Herbal hepatotoxicity: acute hepatitis caused by a Noni preparation (Morinda citrifolia). Eur J Gastroenterol Hepatol 2005;17:445-7. PubMed
  2. Stadlbauer V, Fickert P, Lackner C, et al. Hepatotoxicity of NONI juice: report of two cases. World J Gastroenterol 2005;11:4758-60. PubMed
  3. Yuce B, Gulberg V, Diebold J, Gerbes AL. Hepatitis induced by noni juice from morinda citrifolia: a rare cause of hepatotoxicity or the tip of the iceberg? Digestion 2006;73:167-70.
Moderate

PHENYTOIN (Dilantin)

2 of 2
Theoretically, taking noni fruit juice concomitantly with phenytoin may lower phenytoin levels and increase the risk of seizures.
In one case report, an adult taking phenytoin for partial seizures experienced low serum phenytoin levels while taking noni juice 90-200 mL daily. Serum phenytoin levels increased after decreasing noni juice consumption; similarly, serum phenytoin levels decreased after increasing noni juice consumption. Some researchers believe noni juice may induce cytochrome P450 2C9 enzymes, which would decrease phenytoin levels, but this has not been well studied. Patients may need additional monitoring when starting or stopping noni juice supplementation.
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 concern with pairing noni juice and your phenytoin. Phenytoin keeps seizures in check by quieting overactive electrical signals in the brain, and your body clears it through a liver enzyme called CYP2C9. There's a single case report suggesting noni juice may speed that enzyme up, which could push your phenytoin levels down. Lower levels can mean less seizure protection and a higher chance of breakthrough seizures.

I want to be honest about the evidence: this is anecdotal and theoretical, based on one person, not strong studies. Still, phenytoin is a narrow-window drug where small shifts matter. If you're thinking about starting or stopping noni, please loop in your doctor or pharmacist first, since they may want to check a blood level.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Yu-Chan Kang, Ming-Hong Chen, Shung-Lon Lai. Potentially Unsafe Herb-drug Interactions Between a Commercial Product of Noni Juice and Phenytoin- A Case Report. Acta Neurol Taiwan. 2015 Jun;24(2):43-6.

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

Noni Also Interacts With Other Medications

Noni has 540 moderate, 1 minor known drug interactions in our database — the Phenytoin one above is among them. If you take anything else, check it against the full list below.

Moderate 540 Minor 1 No known interaction 2,289 (incl. Phenytoin)
Taking anything else?

Check Another of Your Medications Against Noni

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

From our Q&A

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

We hold 727 real supplement products containing Noni, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Noni. Your product may carry other ingredients that interact with Phenytoin too, on top of Noni — 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 Noni 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 Noni
Top 25%

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

29 days ago today
Medication Phenytoin
Steady interest

#1,739 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 Noni

What is Noni?

Noni
  • General wellness and energy
  • Inflammation and joint pain
  • Immune support
  • High blood pressure
  • Skin and wound care
  • Digestive complaints

Noni is a tropical fruit used widely in folk medicine and sold mostly as a juice or supplement, but solid human evidence for its many claimed benefits is limited. While moderate juice intake is generally well tolerated, there are rare reports of liver problems, and it should be avoided in pregnancy and breastfeeding. Talk with your pharmacist or doctor before using it, especially if you have kidney or liver disease.

Read the full Noni monograph & all interactions
Medication

About Phenytoin

What Is Phenytoin Used For?

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

Phenytoin is used to treat and prevent seizures. The specific types covered depend on the formulation. Oral extended-release capsules (including Phenytek), chewable tablets (including Dilantin Infatabs and Phenytoin Infatabs), and oral suspension (including Dilantin-125) are used for tonic-clonic (grand mal) and psychomotor (temporal lobe) seizures; most oral forms also cover prevention and treatment of seizures occurring during or after neurosurgery. Chewable tablets and some capsule formulations also cover complex partial seizures.

Parenteral (injectable) phenytoin sodium is used for generalized tonic-clonic status epilepticus (a prolonged, life-threatening seizure emergency) and for prevention and treatment of seizures during neurosurgery. The IV form can also substitute short-term for oral phenytoin when a patient cannot take it by mouth.

See full Phenytoin drug information
Keep checking

Other Drugs & Noni

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

0Major
540Moderate
1Minor
2,288No known interaction
540 Moderate 1 Minor 2,288 No interaction
Moderate

540 interactions

Showing 60 of 540 moderate interactions — see all 540 on the Noni page.

Minor

1 interaction

No interaction 2,288 drugs checked — show the list

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

Showing the 60 most looked-up of 2,288 medications checked with no known interaction — see the full Noni list.

See the full Noni 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
Noni 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 Noni and Phenytoin Together: Common Questions

Can you take Noni 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.
Why are there 2 interactions listed for Noni and Phenytoin?
Phenytoin belongs to more than one drug category, and Noni 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 Noni 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 Noni?

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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.