Drug & supplement interaction

Beet + Ondansetron

Ondansetron brand name: Zofran.

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

Ondansetron falls into 2 drug categories that Beet can interact with; the most serious is rated moderate. Theoretically, beet might increase the levels of CYP3A4 substrates.

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

Beet and Ondansetron

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

Why Are There 2 Interactions?

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

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

1 of 2

Why this applies to Ondansetron

Ondansetron falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Beet interacts with.

Theoretically, beet might increase the levels of CYP3A4 substrates.
In vitro research suggests that betanin, the major pigment in beet, competitively inhibits CYP3A4 in a dose-dependent manner similarly to strong CYP3A4 inhibitor ketoconazole.
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 ondansetron (Zofran). Your body uses an enzyme called CYP3A4 to help break it down. Lab studies suggest the red pigment in beets (betanin) might slow that enzyme. If it did, a bit more ondansetron could linger in your system, which in theory could mean slightly stronger effects or side effects like headache, constipation, dizziness, or tiredness.

I want to be honest though: this is theoretical, based only on test-tube research, not on people eating beets. Normal food amounts of beets are very unlikely to cause trouble. If you're using concentrated beetroot supplements, just mention it to your pharmacist or doctor so they can keep an eye on things.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Lim SH, Bae S, Lee HS, Han HK, Choi CI. Effect of Betanin, the Major Pigment of Red Beetroot (Beta vulgaris L.), on the Activity of Recombinant Human Cytochrome P450 Enzymes. Pharmaceuticals (Basel) 2023;16(9):1224. PubMed
Minor

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

2 of 2

Ondansetron also falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES.

Theoretically, beet might decrease the levels and clinical effects of CYP1A2 substrates.
In vitro research suggests that beet induces CYP1A2 enzymes.
Severity Minor 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 ondansetron (Zofran) and beets. The concern on file is that beet may speed up a liver enzyme called CYP1A2, which is one of the pathways that helps clear ondansetron. If that enzyme works faster, your body could theoretically break down ondansetron a bit quicker, which might make it slightly less effective at holding back nausea and vomiting.

I want to keep this in perspective. This is a minor interaction based only on lab (test tube) research, not real people, so the real-world effect is likely small or none. Ondansetron is not a prodrug, so it doesn't get stronger here. Everyday amounts of beets in food are very unlikely to matter. If you rely on Zofran and want to use concentrated beetroot supplements, just check with your pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Haron MH, Dale O, Martin K, et al. Evaluation of the Herb-Drug Interaction Potential of Commonly Used Botanicals on the US Market with Regard to PXR- and AhR-Mediated Influences on CYP3A4 and CYP1A2. J Diet Suppl 2022. 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

Beet Also Interacts With Other Medications

Beet has 642 moderate, 218 minor known drug interactions in our database — the Ondansetron one above is among them. If you take anything else, check it against the full list below.

Moderate 642 Minor 218 No known interaction 1,970 (incl. Ondansetron)
Taking anything else?

Check Another of Your Medications Against Beet

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

From our Q&A

Questions About Beet or Ondansetron

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

This page covers Beet only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Ondansetron page lists 195 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Lithium (major), St. John's Wort (major) and 1,3-dmaa (moderate).

By severity: 4 major · 145 moderate · 46 minor.

From our pharmacist’s overview on the Ondansetron page

“Ondansetron (Zofran) often stands between you and relentless nausea from chemotherapy or surgery, so read this page carefully. Four of the 195 ingredients rate major.”

Reviewed by 2 · Jul 18, 2026

Open the Ondansetron interaction page

One more smart check

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

We hold 4,785 real supplement products containing Beet, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Beet. Your product may carry other ingredients that interact with Ondansetron too, on top of Beet — 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 Beet and Ondansetron 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 Beet
Top 5%

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

29 days ago today
Medication Ondansetron
Top 25%

#336 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 Beet

What is Beet?

Beet
  • High blood pressure
  • Exercise and athletic performance
  • Heart and circulation support
  • General antioxidant/anti-inflammatory support
  • Liver and digestive support

Beet, especially beetroot juice, is a nitrate-rich food that may modestly lower blood pressure and slightly improve exercise performance in some people. It is generally safe as a food, but supplement effects are modest and not a substitute for prescribed treatment, so talk with your pharmacist or doctor before relying on it.

Read the full Beet monograph & all interactions
Medication

About Ondansetron

What Is Ondansetron Used For?

Brand name: Zofran

Ondansetron is used to prevent nausea and vomiting in several situations. Oral forms (tablets, orally disintegrating tablets, and oral solution) are approved to prevent nausea and vomiting from highly or moderately emetogenic (nausea-causing) cancer chemotherapy, from radiation therapy to the abdomen or whole body, and from surgery.

Ondansetron injection (given intravenously or intramuscularly in a clinical setting) is approved to prevent nausea and vomiting from emetogenic cancer chemotherapy — including high-dose cisplatin — in adults and children as young as 6 months old, as well as to prevent postoperative nausea and vomiting.

See full Ondansetron drug information
Keep checking

Other Drugs & Beet

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

0Major
642Moderate
218Minor
1,969No known interaction
642 Moderate 218 Minor 1,969 No interaction
Moderate

642 interactions

Showing 60 of 642 moderate interactions — see all 642 on the Beet page.

Minor

218 interactions

Showing 60 of 218 minor interactions — see all 218 on the Beet page.

No interaction 1,969 drugs checked — show the list

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

Showing the 60 most looked-up of 1,969 medications checked with no known interaction — see the full Beet list.

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

Can you take Beet with Ondansetron?
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 Beet and Ondansetron?
Ondansetron belongs to more than one drug category, and Beet 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 Beet and Ondansetron 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 Ondansetron and Beet?

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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.