Drug & supplement interaction

Ketogenic Diet + Ondansetron

Ondansetron brand name: Zofran.

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 Ketogenic Diet and Ondansetron 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

Ketogenic Diet and Ondansetron

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 Ondansetron and Ketogenic Diet in our sources. This does not guarantee that the combination is completely free of risk — research on Ketogenic Diet alongside specific medications may be limited.

Ketogenic Diet is an eating pattern rather than something you take. Ask your pharmacist or doctor before changing how you eat while on a prescribed medicine: some medicines are dosed around meals, and a change in diet can change how they work. 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.

Ketogenic Diet safety at a glance

Ketogenic Diet overall Use caution Generally manageable for healthy adults short-term, but it can cause side effects and is not safe for everyone.
Pregnancy Use caution Strict keto is generally not recommended in pregnancy without medical supervision because of nutrient and growth concerns.
Breastfeeding Possibly Unsafe When used orally without medical supervision. While rare, there are several case reports of lactation ketoacidosis thought to be associated with adherence to ca... Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Ondansetron and Ketogenic Diet? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Ondansetron

Interactions in our licensed database are recorded against drug classes, not just single drug names. Ondansetron is filed under 7 classifications — including serotonergic drugs, serotonergic drugs, cytochrome p450 1a2 (cyp1a2) substrates. Ketogenic Diet has documented interactions with 6 drug classes — the most serious being anticonvulsants (moderate), antidiabetes drugs (moderate) and carbonic anhydrase inhibitors (moderate) — and none of Ondansetron’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Ketogenic Diet Does Interact With Other Medications

Ketogenic Diet has 137 moderate, 122 minor known drug interactions in our database — Ondansetron isn’t one of them. If you take anything else, check it against the full list below.

Moderate 137 Minor 122 No known interaction 2,571 (incl. Ondansetron)
Taking anything else?

Check Another of Your Medications Against Ketogenic Diet

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

What to actually watch for

No Interaction Found — But Data Suggests Ketogenic Diet and Ondansetron 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 following Ketogenic Diet while taking the medicine can make those effects more likely to turn up, and harder to pin on one or the other if they do. One of them is worth acting on rather than waiting out — marked below.

  • An irregular heartbeat Worth acting on Additional detail

    Ketogenic Diet

    “Orally, the ketogenic diet has been reported to increase levels of total cholesterol and triglycerides. The development of increased lipid levels can occur in as many as 60% of diet adherents. Plasma lipid levels usually normalize by 12 months, although hypercholesterolemia and hypertriglyceridemia have occurred in some patients. In very few cases, the ketogenic diet might need to be stopped.”

    Ketogenic Diet · Natural Medicines adverse-effect record, reported in atherosclerosis.

    6 sources cited
    1. 96903. Liu H, Yang Y, Wang Y, et al. Ketogenic diet for treatment of intractable epilepsy in adults: A meta-analysis of observational studies. Epilepsia Open. 2018;3(1):9-17. PubMed
    2. 96957. Martin-McGill KJ, Srikandarajah N, Marson AG, Tudur Smith C, Jenkinson MD. The role of ketogenic diets in the therapeutic management of adult and paediatric gliomas: a systematic review. CNS Oncol. 2018;7(2):CNS17.
    3. 96966. Lima PA, de Brito Sampaio LP, Damasceno NR. Ketogenic diet in epileptic children: impact on lipoproteins and oxidative stress. Nutr Neurosci. 2015;18(8):337-44. PubMed
    4. 96968. Ulamek-Koziol M, Pluta R, Bogucka-Kocka A, Czuczwar SJ. To treat or not to treat drug-refractory epilepsy by the ketogenic diet? That is the question. Ann Agric Environ Med. 2016;23(4):533-536. PubMed
    5. 97639. Ashrafi MR, Hosseini SA, Zamani GR, et al. The efficacy of the ketogenic diet in infants and young children with refractory epilepsies using a formula-based powder. Acta Neurol Belg. 2017;117(1):175-182. PubMed
    6. 97647. Klepper J, Leiendecker B, Heussinger N, Lausch E, Bosch F. Severe hypertriglyceridemia in Glut1D on ketogenic Diet. Neuropediatrics. 2016;47(2):132-6. PubMed

    Ondansetron

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

Reported for Ketogenic Diet but not commonly for Ondansetron: stomach upset, a higher chance of infection, a severe allergic reaction and blood clots.

Effects for Ondansetron come from the ADVERSE REACTIONS section of its FDA label; effects for Ketogenic Diet come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 121,840 voluntary FDA FAERS reports for Ondansetron that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Ketogenic Diet in Pregnancy & Breastfeeding

Lactation Possibly Unsafe

When used orally without medical supervision. While rare, there are several case reports of lactation ketoacidosis thought to be associated with adherence to calorie-restricted and non-calorie-restricted ketogenic diets. The increased metabolic demand of breastfeeding, especially if exclusively breastfeeding, may increase the risk of lactation ketoacidosis in these individuals. In addition to metabolic changes, symptoms included nausea, vomiting, dizziness, dyspnea, lethargy, epigastric pain, and chest pain. In one case, the lactation ketoacidosis was life-threatening and required treatment in the intensive care unit with non-invasive ventilatory support and dextrose and insulin infusions. In this case, the patient was following a calorie-restricted, ketogenic diet and had lost 19 pounds over 3 weeks.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Ketogenic Diet 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 Ketogenic Diet 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 Ketogenic Diet 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

How much people look this up

Where Ketogenic Diet 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 Ketogenic Diet
Steady interest

#1,001 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Ondansetron
Steady interest

#1,687 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 Ketogenic Diet reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Ketogenic Diet and Ondansetron records this page draws on were last updated July 11, 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 .
Eating pattern

About Ketogenic Diet

What is Ketogenic Diet?

  • Weight loss
  • Type 2 diabetes and blood sugar control
  • Drug-resistant epilepsy (especially in children)
  • Reducing appetite
  • Athletic and metabolic interest

The ketogenic diet is a very low-carbohydrate, high-fat eating plan that shifts the body to burn fat for fuel. It has the strongest evidence as a medical therapy for hard-to-treat epilepsy and may help short-term weight loss and blood sugar, but it can be hard to sustain and is not right for everyone. Talk with a doctor or pharmacist before starting, especially if you have a medical condition or take medication.

Whole-food eating plan; sometimes paired with MCT oil or exogenous ketone supplements

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

Ketogenic Diet: dosing

There is no single "dose" for a ketogenic diet. Instead, it is defined by how much of your calories come from fat, protein, and carbohydrates. Strict therapeutic versions used for epilepsy keep carbohydrates very low and are calculated carefully by a medical team. More relaxed low-carb versions allow somewhat more carbohydrate.If you try keto on your own, follow guidance from a reputable source and pay attention to food quality, hydration, and electrolytes. Children should only follow a medical ketogenic diet under specialist supervision.

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

Read the full Ketogenic Diet 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.

Most-Reported Side Effects for Ondansetron

From FAERS, the FDA’s public side-effect reporting system (121,840 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Nausea 14,459 reports
Fatigue 10,275 reports
Diarrhea 9,488 reports
Vomiting 8,777 reports
Dyspnea 5,971 reports
See full Ondansetron drug information
Keep checking

Other Drugs & Ketogenic Diet

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

0Major
137Moderate
122Minor
2,570No known interaction
137 Moderate 122 Minor 2,570 No interaction
Moderate

137 interactions

Showing 60 of 137 moderate interactions — see all 137 on the Ketogenic Diet page.

Minor

122 interactions

Showing 60 of 122 minor interactions — see all 122 on the Ketogenic Diet page.

No interaction 2,570 drugs checked — show the list

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

Showing the 60 most looked-up of 2,570 medications checked with no known interaction — see the full Ketogenic Diet list.

See the full Ketogenic Diet interactions page
See every supplement checked against Ondansetron, ranked by severity
Evidence & sources

Ketogenic Diet References

The 72 references that drive our Ketogenic Diet 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. Liu H, Yang Y, Wang Y, et al. Ketogenic diet for treatment of intractable epilepsy in adults: A meta-analysis of observational studies. Epilepsia Open. 2018;3(1):9-17. PubMed
  2. Yancy WS Jr, Westman EC, McDuffie JR, et al. A randomized trial of a low-carbohydrate diet vs orlistat plus a low-fat diet for weight loss. Arch Intern Med. 2010;170(2):136-45. PubMed
  3. Goday A, Bellido D, Sajoux I, et al. Short-term safety, tolerability and efficacy of a very low-calorie-ketogenic diet interventional weight loss program versus hypocaloric diet in patients with type 2 diabetes mellitus. Nutr Diabetes. 2016;6(9):e230. PubMed
  4. Saslow LR, Mason AE, Kim S, et al. An online intervention comparing a very low-carbohydrate ketogenic diet and lifestyle recommendations versus a plate method diet in overweight individuals with type 2 diabetes: A randomized controlled trial. J Med Intern
  5. Hussain TA, Mathew TC, Dashti AA, Asfar S, Al-Zaid N, Dashti HM. Effect of low-calorie versus low-carbohydrate ketogenic diet in type 2 diabetes. Nutrition. 2012;28(10):1016-21. PubMed
  6. Martin-McGill KJ, Srikandarajah N, Marson AG, Tudur Smith C, Jenkinson MD. The role of ketogenic diets in the therapeutic management of adult and paediatric gliomas: a systematic review. CNS Oncol. 2018;7(2):CNS17.
  7. Michaels JD, Hoss E, DiCaudo DJ, Price H. Prurigo pigmentosa after a strict ketogenic diet. Pediatr Dermatol. 2015;32(2):248-51. PubMed
  8. Hawkes CP, Levine MA. Ketotic hypercalcemia: a case series and description of a novel entity. J Clin Endocrinol Metab. 2014;99(5):1531-6. PubMed
  9. Lima PA, de Brito Sampaio LP, Damasceno NR. Ketogenic diet in epileptic children: impact on lipoproteins and oxidative stress. Nutr Neurosci. 2015;18(8):337-44. PubMed
  10. Ulamek-Koziol M, Pluta R, Bogucka-Kocka A, Czuczwar SJ. To treat or not to treat drug-refractory epilepsy by the ketogenic diet? That is the question. Ann Agric Environ Med. 2016;23(4):533-536. PubMed
  11. Zahra A, Fath MA, Opat E, et al. Consuming a ketogenic diet while receiving radiation and chemotherapy for locally advanced lung cancer and pancreatic cancer: The University of Iowa experience of two phase 1 clinical trials. Radiat Res. 2017;187(6):743-75 PubMed
  12. Ahn WK, Park S, Kim HD. Protein-losing enteropathy as a complication of the ketogenic diet. Yonsei Med J. 2017;58(4):891-893. PubMed
  13. Winter SF, Loebel F, Dietrich J. Role of ketogenic metabolic therapy in malignant glioma: A systematic review. Crit Rev Oncol Hematol. 2017;112:41-58. PubMed
  14. Kverneland M, Selmer KK, Nakken KO, Iversen PO, Taubøll E. A prospective study of the modified Atkins diet for adults with idiopathic generalized epilepsy. Epilepsy Behav. 2015;53:197-201. PubMed
  15. Ashrafi MR, Hosseini SA, Zamani GR, et al. The efficacy of the ketogenic diet in infants and young children with refractory epilepsies using a formula-based powder. Acta Neurol Belg. 2017;117(1):175-182. 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

Following Ketogenic Diet While Taking Ondansetron: Common Questions

Is it safe to follow Ketogenic Diet while taking Ondansetron?
We do not list a known interaction between Ketogenic Diet and Ondansetron. 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 Ketogenic Diet and Ondansetron 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.
How was the Ketogenic Diet and Ondansetron combination checked?
Interactions in our licensed database are recorded against drug classes. Ondansetron is filed under 7 classifications, and Ketogenic Diet has documented interactions with 6 drug classes — none of Ondansetron's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Ketogenic Diet interact with any other medications?
Yes. Ketogenic Diet has 259 documented drug interactions in our database — Ondansetron is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Ondansetron interact with any supplements?
Yes. Ondansetron has documented interactions with 195 supplements in our database — Ketogenic Diet is not one of them. The Ondansetron 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

Ketogenic Diet monograph Uses, safety profile, and every drug interaction in one place Ondansetron drug information The full plain-English guide to this medication Ondansetron supplement interactions Every supplement checked against Ondansetron, 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 72 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

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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.