Drug & supplement interaction

Turpentine Oil + Ondansetron

Ondansetron brand name: Zofran.

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

Turpentine Oil has a minor interaction with Ondansetron. There is some concern that turpentine oil can inhibit CYP1A2 enzyme activity by up to 90% via induction of inflammation and subsequent downregulation of CYP activity.

Read the full interaction report
SeverityMinor
LikelihoodUnlikely
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Turpentine Oil and Ondansetron

Here is the interaction we found between these two, with the evidence behind it.

Minor

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

Why this applies to Ondansetron

Ondansetron falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Turpentine Oil interacts with.

There is some concern that turpentine oil can inhibit CYP1A2 enzyme activity by up to 90% via induction of inflammation and subsequent downregulation of CYP activity. However, animal research suggests that turpentine oil does not affect the metabolism of phenacetin, a CYP1A2 substrate, despite inducing inflammation.
Some medications metabolized by CYP1A2 include clozapine (Clozaril), cyclobenzaprine (Flexeril), fluvoxamine (Luvox), haloperidol (Haldol), imipramine (Tofranil), mexiletine (Mexitil), olanzapine (Zyprexa), pentazocine (Talwin), propranolol (Inderal), tacrine (Cognex), theophylline, tizanidine (Zanaflex), zileuton (Zyflo), zolmitriptan (Zomig), and others.
Severity Minor Likelihood Unlikely Evidence D

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist for ondansetron (Zofran) and turpentine oil. There's a theory that turpentine oil could slow down a liver enzyme called CYP1A2, which is one of several enzymes that help clear ondansetron from your body. If that enzyme were blocked, a bit more ondansetron could hang around, which in theory might mean more of its usual side effects like headache, constipation, or feeling lightheaded.

The good news: this concern comes only from lab and animal research, not from people, and even one animal study didn't see a real effect. Ondansetron is also broken down by several enzymes, so one being nudged rarely matters much. I wouldn't lose sleep over it, but check with your pharmacist or doctor if you're using turpentine products.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Prasad VG, Vivek Ch, Anand Kumar P, Ravi Kumar P, Rao GS. Turpentine oil induced inflammation decreases absorption and increases distribution of phenacetin without altering its elimination process in rats. Eur J Drug Metab Pharmacokinet 2015;40(1):23-8. 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

Turpentine Oil Also Interacts With Other Medications

Turpentine Oil has 198 moderate, 177 minor known drug interactions in our database — the Ondansetron one above is one of them. If you take anything else, check it against the full list below.

Moderate 198 Minor 177 No known interaction 2,455 (incl. Ondansetron)
Taking anything else?

Check Another of Your Medications Against Turpentine Oil

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

From our Q&A

Questions About Turpentine Oil 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 Turpentine Oil 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 Turpentine Oil 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 Turpentine Oil 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 Turpentine Oil
Top half

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

29 days ago today
Medication Ondansetron
Top half

#1,372 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 Turpentine Oil

What is Turpentine Oil?

Turpentine Oil
  • Muscle and joint aches (topical)
  • Cough and congestion (chest rubs)
  • Minor skin conditions
  • Antiseptic
  • Toothache (traditional)

Turpentine oil is a strong-smelling pine resin product used mostly in tiny amounts in topical rubs for muscle aches and congestion. It can be dangerous and even deadly if swallowed, and reliable evidence for health benefits is very limited. Never drink turpentine oil, and only use diluted, purified products on the skin with care.

Read the full Turpentine Oil 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 & Turpentine Oil

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

0Major
198Moderate
177Minor
2,454No known interaction
198 Moderate 177 Minor 2,454 No interaction
Moderate

198 interactions

Showing 60 of 198 moderate interactions — see all 198 on the Turpentine Oil page.

Minor

177 interactions

Showing 60 of 177 minor interactions — see all 177 on the Turpentine Oil page.

No interaction 2,454 drugs checked — show the list

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

Showing the 60 most looked-up of 2,454 medications checked with no known interaction — see the full Turpentine Oil list.

See the full Turpentine Oil 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
Turpentine Oil 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 Turpentine Oil and Ondansetron Together: Common Questions

Can you take Turpentine Oil with Ondansetron?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Turpentine Oil and Ondansetron interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Ondansetron and Turpentine Oil?

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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.