Drug & supplement interaction

Olive + Phenytoin

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

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Olive and Phenytoin in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Olive and Phenytoin

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Phenytoin and Olive in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

Worth understanding: our licensed dataset holds no drug-interaction record for Olive at all — not against Phenytoin, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Olive safety at a glance

Olive overall Use caution Olive as food and oil is very safe, but concentrated supplements are less studied.
Pregnancy Use caution Olive oil and olives as food are fine, but avoid concentrated supplements unless your doctor approves.
Breastfeeding Use caution Olives and olive oil are safe foods, but the safety of concentrated supplements is not well known.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Phenytoin and Olive? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Olive and Phenytoin May Share a Side Effect

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Headache Additional detail

    Olive

    “Orally, three patients in one clinical trial reported headache after using olive leaf extract.”

    Olive · Natural Medicines adverse-effect record, reported in cluster headache.

    1 source cited
    1. 101860. Somerville V, Moore R, Braakhuis A. The effect of olive leaf extract on upper respiratory illness in high school athletes: A randomised control trial. Nutrients. 2019;11(2). pii: E358. PubMed

    Phenytoin

    Listed in the ADVERSE REACTIONS section of the FDA label for Phenytoin. Read the label on DailyMed ›

Reported for Olive but not commonly for Phenytoin: stomach upset and acne.

Effects for Phenytoin come from the ADVERSE REACTIONS section of its FDA label; effects for Olive come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

From our Q&A

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

We hold 2,653 real supplement products containing Olive, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Olive. Even though Olive itself has no known interaction with Phenytoin, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Olive 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 Olive
Top 10%

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

29 days ago today
Medication Phenytoin
Top half

#922 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Olive reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Olive and Phenytoin records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Olive

What is Olive?

Olive
  • Heart health
  • High blood pressure
  • High cholesterol
  • Antioxidant support
  • Antimicrobial
  • General wellness

Olive comes from the same tree that gives us olives and olive oil, and its leaf and fruit contain antioxidant compounds like oleuropein and hydroxytyrosol. Olive oil as part of a Mediterranean diet is well-studied for heart health, but supplements made from olive leaf or fruit extract have less solid evidence. Talk to your pharmacist or doctor before starting any supplement, especially if you have health conditions or take medications.

Olea europaea · Oleaceae · Leaves and fruit (including olive fruit pulp and olive oil) · Capsules, tablets, liquid extracts, teas, olive leaf extract, olive oil

An interaction check asks whether these two react with each other — it does not ask whether Olive is a good idea for someone in your situation. Here is what our Olive record says about it on its own.

Olive: dosing

There is no official standard dose for olive leaf or olive fruit supplements. Products vary widely in their strength and in how much oleuropein or hydroxytyrosol they contain.The best advice is to follow the directions on the product label and not exceed the recommended amount.

From our Olive monograph — the full record covers uses, side effects and every documented interaction.

Read the full Olive 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.

Most-Reported Side Effects for Phenytoin

From FAERS, the FDA’s public side-effect reporting system (40,278 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Convulsion 3,522 reports
Seizure 3,095 reports
Toxicity to various agents 1,888 reports
Fall 1,604 reports
Dizziness 1,539 reports
See full Phenytoin drug information
Keep checking

Other Drugs & Olive

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Olive list.

See the full Olive interactions page
See every supplement checked against Phenytoin, ranked by severity
Evidence & sources

Olive References

The 2 references that drive our Olive monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Liccardi G, D'Amato M, D'Amato G. Oleaceae pollinosis: a review. Int Arch Allergy Immunol 1996;111:210-7. PubMed
  2. Somerville V, Moore R, Braakhuis A. The effect of olive leaf extract on upper respiratory illness in high school athletes: A randomised control trial. Nutrients. 2019;11(2). pii: E358. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Olive and Phenytoin Together: Common Questions

Is it safe to take Olive with Phenytoin?
We do not list a known interaction between Olive and Phenytoin. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Olive and Phenytoin have any of the same side effects?
Yes — our sources link each of them separately to one of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Does Phenytoin interact with any supplements?
Yes. Phenytoin has documented interactions with 224 supplements in our database — Olive is not one of them. The Phenytoin interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Olive monograph Uses, safety profile, and every drug interaction in one place Phenytoin drug information The full plain-English guide to this medication Phenytoin supplement interactions Every supplement checked against Phenytoin, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Phenytoin and Olive?

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.