Drug & supplement interaction

Garlic + Etoposide

Etoposide brand names: VePesid, VP16, Etopophos.

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

Garlic has a moderate interaction with Etoposide. Theoretically, garlic products containing allicin might induce intestinal CYP3A4 and inhibit hepatic CYP3A4.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceB
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Garlic and Etoposide

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

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Etoposide

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

Theoretically, garlic products containing allicin might induce intestinal CYP3A4 and inhibit hepatic CYP3A4. This may increase or decrease levels of drugs metabolized by CYP3A4.
Some human research suggests that garlic may induce INTESTINAL CYP3A4, reducing levels of drugs metabolized by this enzyme. This is primarily based on a study showing that taking a specific allicin-containing garlic product (GarliPure Maximum Allicin Formula, Natrol Inc.) twice daily for 3 days reduces saquinavir levels by approximately 50%. It is speculated that the allicin constituent induced CYP3A4 in the gut mucosa. Another study shows that giving docetaxel intravenously, bypassing the CYP3A4 enzymes in the gut mucosa, along with the same specific garlic product for 12 consecutive days, does not affect docetaxel levels. Conversely, there is concern that garlic may inhibit HEPATIC CYP3A4. In a single case report, increased tacrolimus levels and liver injury occurred in a liver transplant patient after taking a specific garlic supplement (Garlicin Cardio, Nature's Way) at up to three times the manufacturer recommended dose for 7 days. Several other studies have evaluated the impact of other garlic formulations on CYP3A4 substrates and have found no effect. Most of the products in these studies provided little or no allicin.
Severity Moderate Likelihood Possible Evidence B

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 thing with garlic and your etoposide. Etoposide is an active chemo drug (not a prodrug), and your body relies on an enzyme called CYP3A4 to help process it. Concentrated garlic supplements, especially the kind rich in allicin, can nudge this enzyme in different directions. In the gut they may speed it up, which could lower how much etoposide your body absorbs and make it work less well. In the liver they may slow it down, which could let levels climb and bring more side effects like low blood counts, nausea, mouth sores, or hair loss.

Honestly, the evidence here is mixed and partly theoretical, and ordinary garlic in cooking is unlikely to be a problem. But since this is cancer treatment, please don't add a garlic supplement without checking with your oncologist or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Piscitelli SC, Burstein AH, Welden N, et al. The effect of garlic supplements on the pharmacokinetics of saquinavir. Clin Infect Dis 2002;34:234-8. PubMed
  2. Markowitz JS, Devane CL, Chavin KD, et al. Effects of garlic (Allium sativum L.) supplementation on cytochrome P450 2D6 and 3A4 activity in healthy volunteers. Clin Pharmacol Ther 2003;74:170-7.. PubMed
  3. Gurley BJ, Gardner SF, Hubbard MA, et al. Cytochrome P450 phenotypic ratios for predicting herb-drug interactions in humans. Clin Pharmacol Ther 2002;72:276-87.. PubMed
  4. Dhamija P, Malhotra S, Pandhi P. Effect of oral administration of crude aqueous extract of garlic on pharmacokinetic parameters of isoniazid and rifampicin in rabbits. Pharmacology 2006;77:100-4. PubMed
  5. Cox MC, Low J, Lee J, et al. Influence of garlic (Allium sativum) on the pharmacokinetics of docetaxel. Clin Cancer Res 2006;12:4636-40.
  6. Jalloh MA, Gregory PJ, Hein D, et al. Dietary supplement interactions with antiretrovirals: a systematic review. Int J STD AIDS. 2017 Jan;28(1):4-15. PubMed
  7. Gallicano K, Foster B, Choudhri S. Effect of short-term administration of garlic supplements on single-dose ritonavir pharmacokinetics in healthy volunteers. Br J Clin Pharmacol. 2003;55(2):199-202. PubMed
  8. Shaikh SA, Tischer S, Choi EK, Fontana RJ. Good for the lung but bad for the liver? Garlic-induced hepatotoxicity following liver transplantation. J Clin Pharm Ther. 2017;42(5):646-648. 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

Garlic Also Interacts With Other Medications

Garlic has 988 moderate known drug interactions in our database — the Etoposide one above is one of them. If you take anything else, check it against the full list below.

Moderate 988 No known interaction 1,842 (incl. Etoposide)
Taking anything else?

Check Another of Your Medications Against Garlic

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

From our Q&A

Questions About Garlic or Etoposide

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

This page covers Garlic only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Etoposide page lists 152 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Apple (major), Grapefruit (major), St. John's Wort (major) and Sweet Orange (major).

By severity: 5 major · 107 moderate · 40 minor.

From our pharmacist’s overview on the Etoposide page

“Chemotherapy is unforgiving of level swings, and swings are exactly what most of this list can cause for etoposide (VePesid, Etopophos). Of the 152 supplements and herbs on file, 121 can change how your liver clears etoposide through the CYP3A4 enzyme, meaning too little drug and an undertreated cancer, or too much and harsher toxicity.”

Reviewed by 2 · Jul 18, 2026

Open the Etoposide interaction page

One more smart check

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

We hold 4,118 real supplement products containing Garlic, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Garlic. Your product may carry other ingredients that interact with Etoposide too, on top of Garlic — 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 Garlic and Etoposide 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 Garlic
Top 5%

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

29 days ago today
Medication Etoposide
Top half

#1,090 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 Garlic

What is Garlic?

Garlic
  • High blood pressure
  • High cholesterol
  • Heart health
  • Immune support and common cold
  • Antimicrobial uses

Garlic is a common food and supplement that may modestly help with blood pressure and cholesterol, though the evidence is mixed and effects are usually small. It is generally safe in food amounts, but concentrated supplements can cause stomach upset, breath and body odor, and a higher risk of bleeding. Talk with your pharmacist or doctor before taking garlic supplements, especially if you take other medicines.

Read the full Garlic monograph & all interactions
Medication

About Etoposide

What Is Etoposide Used For?

Brand names: VePesid, VP16, Etopophos

Etoposide injection (available as Avopef, Etopophos, Toposar, and Etoposide) is used to treat refractory testicular tumors — cancers that have already been treated with surgery, radiation, and other chemotherapy — always in combination with other cancer drugs. It is also used for small cell lung cancer (SCLC) as a first-line treatment, given together with other chemotherapy and, in the case of Avopef, with immunotherapy as well.

Etoposide capsules (VePesid and Etoposide capsules) are approved for small cell lung cancer as first-line treatment in combination with other chemotherapy agents. Capsule forms are not approved for testicular cancer, as the label notes that adequate data on their use in that setting are not available.

See full Etoposide drug information
Keep checking

Other Drugs & Garlic

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

0Major
988Moderate
0Minor
1,841No known interaction
988 Moderate 1,841 No interaction
Moderate

988 interactions

Showing 60 of 988 moderate interactions — see all 988 on the Garlic page.

No interaction 1,841 drugs checked — show the list

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

Showing the 60 most looked-up of 1,841 medications checked with no known interaction — see the full Garlic list.

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

Can you take Garlic with Etoposide?
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.
How serious is the Garlic and Etoposide 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 Etoposide and Garlic?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.