Drug & supplement interaction

Sage + 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 4 drug categories that Sage can interact with; the most serious is rated moderate. Theoretically, taking sage might increase the sedative and adverse effects of CNS depressants.

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

Sage and Phenytoin

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

Why Are There 4 Interactions?

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

Moderate

CNS DEPRESSANTS

1 of 4

Why this applies to Phenytoin

Phenytoin falls under CNS DEPRESSANTS — the group Sage interacts with.

Theoretically, taking sage might increase the sedative and adverse effects of CNS depressants.
Some constituents of sage have CNS depressant 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 sage and your Dilantin (phenytoin). The concern on file is fairly mild and mostly theoretical, based on lab work rather than studies in people. Some natural compounds in sage seem to have a calming, sedative-like effect on the brain. Phenytoin can already cause drowsiness, dizziness, unsteadiness, and trouble with coordination, so the worry is that piling sage on top might nudge those effects a little stronger.

The sage you sprinkle on dinner almost certainly won't matter. Concentrated sage extracts or the essential oil are the products to be cautious with. Phenytoin is a finicky medication where small changes can count, so before you start a daily sage supplement, run it past your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Perry NS, Bollen C, Perry EK, Ballard C. Salvia for dementia therapy: review of pharmacological activity and pilot tolerability clinical trial. Pharmacol Biochem Behav 2003;75:651-9.. PubMed
Moderate

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES

2 of 4

Phenytoin also falls under CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES.

Theoretically, sage might increase the levels and clinical effects of drugs metabolized by CYP2C19.
In vitro evidence suggests that aqueous extracts of sage can inhibit CYP2C19. So far, 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 phenytoin (Dilantin). Lab studies hint that sage may slow down a liver enzyme called CYP2C19, which is one of the pathways your body uses to clear phenytoin. If that pathway slows, phenytoin could build up in your blood. Phenytoin is what we call a narrow therapeutic index drug, meaning the line between a helpful level and a too-high level is thin, so even small shifts matter.

If levels climbed, you might notice signs like dizziness, unsteady walking, slurred speech, double vision, or drowsiness. Now, the honest part: this is only theoretical lab evidence and hasn't been seen in real people. Cooking with sage is very unlikely to cause trouble, but concentrated extracts or the oil are a different story. Please check with your pharmacist or doctor before adding sage supplements.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Foster BC, Vandenhoek S, Hana J, et al. In vitro inhibition of human cytochrome P450-mediated metabolism of marker substrates by natural products. Phytomedicine 2003;10:334-42.. PubMed
Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

3 of 4

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

Theoretically, sage might increase the levels and clinical effects of drugs metabolized by CYP2C9.
In vitro evidence suggests that aqueous extracts of sage can inhibit CYP2C9. So far, 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 phenytoin and sage. Your body clears phenytoin mainly through a liver enzyme called CYP2C9. In lab studies, water-based sage extracts seemed to slow that same enzyme down a bit. If that happened in real life, phenytoin could build up in your blood, and since it's a drug where the safe range is narrow, even a small jump can cause trouble: dizziness, unsteady walking, slurred speech, double vision, or feeling very drowsy.

Now, the honest part. This is only a theoretical concern from test-tube work, and it hasn't actually been seen in people. A little sage in cooking is very unlikely to matter. Concentrated extracts or sage oil taken daily are a different story, so check with your pharmacist or doctor before adding them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Foster BC, Vandenhoek S, Hana J, et al. In vitro inhibition of human cytochrome P450-mediated metabolism of marker substrates by natural products. Phytomedicine 2003;10:334-42.. PubMed
Moderate

ANTICONVULSANTS

4 of 4

Phenytoin also falls under ANTICONVULSANTS.

Theoretically, sage might interfere with the clinical effects of anticonvulsant drugs.
Some species of sage can cause convulsions when consumed in large quantities.
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 is the honest picture with sage and your phenytoin (Dilantin). Phenytoin is a seizure medicine that works by calming overactive electrical signals in the brain. The concern on file is mostly theoretical and comes from lab and animal studies, not from people. The worry is two-fold: certain concentrated sage extracts or essential oils contain compounds like thujone that, in large amounts, can actually lower the seizure threshold and potentially trigger convulsions, which works against what phenytoin is trying to do.

Phenytoin is a narrow therapeutic index drug, meaning even small shifts can matter, so this is worth respecting. The good news: normal cooking amounts of sage in food are very unlikely to cause a problem. It is concentrated supplements and the essential oil to be cautious with. Please check with your pharmacist or doctor before adding a sage supplement.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Perry NB, Anderson RE, Brennan NJ, et al. Essential oils from dalmatian sage (Salvia officinalis l.): variations among individuals, plant parts, seasons, and sites. J Agric Food Chem 1999;47:2048-54..

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

Sage Also Interacts With Other Medications

Sage has 1,295 moderate 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 1,295 No known interaction 1,535 (incl. Phenytoin)
Taking anything else?

Check Another of Your Medications Against Sage

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

From our Q&A

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

We hold 718 real supplement products containing Sage, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Sage. Your product may carry other ingredients that interact with Phenytoin too, on top of Sage — 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 Sage 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 Sage
Top 25%

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

29 days ago today
Medication Phenytoin
Steady interest

#1,761 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 Sage

What is Sage?

Sage
  • Sore throat and mouth irritation
  • Digestive upset
  • Excessive sweating
  • Memory and thinking
  • Menopause symptoms (hot flashes)
  • General antioxidant support

Sage is a common kitchen herb that is generally safe in food amounts and is traditionally used for sore throats, digestion, sweating, and memory. Some early research is encouraging for sore throat and menopausal hot flashes, but most uses are not well proven. Concentrated extracts and the essential oil should be used carefully because high doses contain a compound called thujone, which can be harmful.

Read the full Sage 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 & Sage

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

0Major
1,295Moderate
0Minor
1,534No known interaction
1,295 Moderate 1,534 No interaction
Moderate

1,295 interactions

Showing 60 of 1,295 moderate interactions — see all 1,295 on the Sage page.

No interaction 1,534 drugs checked — show the list

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

Showing the 60 most looked-up of 1,534 medications checked with no known interaction — see the full Sage list.

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

Can you take Sage 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 4 interactions listed for Sage and Phenytoin?
Phenytoin belongs to more than one drug category, and Sage 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 Sage 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 Sage?

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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.