Drug & supplement interaction

Ginkgo + Voriconazole

Voriconazole brand name: Vfend.

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

Voriconazole falls into 3 drug categories that Ginkgo can interact with; the most serious is rated moderate. Theoretically, ginkgo might decrease levels of drugs metabolized by CYP2C19.

Read the full interaction report
SeverityModerate
LikelihoodProbable
Interactions3
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Ginkgo and Voriconazole

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Ginkgo interacts with whole categories of medication. Voriconazole falls into 3 of those categories, so it can interact with Ginkgo in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES

1 of 3

Why this applies to Voriconazole

Voriconazole falls under CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES — the group Ginkgo interacts with.

Theoretically, ginkgo might decrease levels of drugs metabolized by CYP2C19.
Some clinical research shows that a specific ginkgo leaf extract (Remembrance, Herbs Product LTD) 140 mg twice daily can induce CYP2C19 enzymes and potentially decrease levels of drugs metabolized by these enzymes. However, other clinical research shows that taking ginkgo 120 mg twice daily for 12 days has no effect on levels of drugs metabolized by CYP2C19.
Severity Moderate Likelihood Probable Evidence B

Interaction 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..

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

Here's the concern with these two together. Your body clears voriconazole using a liver enzyme called CYP2C19, and some research suggests ginkgo can speed that enzyme up. If it does, voriconazole could be cleared a little faster, which may drop its levels in your blood. Since this is an antifungal fighting a serious infection, lower levels could mean it doesn't work as well against the infection you're treating.

That said, the evidence here is shaky. One study saw this effect, another saw none at all, and much of it is theoretical. Still, because voriconazole is a drug where blood levels really matter, I'd play it safe. Please check with your pharmacist or doctor before pairing ginkgo with it rather than stopping anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Yin OQ, Tomlinson B, Waye MM, et al. Pharmacogenetics and herb-drug interactions: experience with Ginkgo biloba and omeprazole. Pharmacogenetics 2004;14:841-50. PubMed
  2. Lei, H. P., Wang, G., Wang, L. S., Ou-yang, D. S., Chen, H., Li, Q., Zhang, W., Tan, Z. R., Fan, L., He, Y. J., and Zhou, H. H. Lack of effect of Ginkgo biloba on voriconazole pharmacokinetics in Chinese volunteers identified as CYP2C19 poor and extensiv
Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

2 of 3

Voriconazole also falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES.

Theoretically, ginkgo might increase levels of drugs metabolized by CYP2C9.
In vitro, a specific standardized extract of ginkgo leaf (EGb 761) inhibits CYP2C9 activity . The terpenoid (ginkgolides) and flavonoid (quercetin, kaempferol, etc.) constituents seem to be responsible for this effect. Most ginkgo extracts contain some amount of these constituents. Therefore, other ginkgo leaf extracts might also inhibit the CYP2C9 enzyme. However, clinical research suggests that ginkgo might not have a significant effect on CYP2C9 in humans. Ginkgo does not seem to significantly affect the pharmacokinetics of CYP2C9 substrates diclofenac or tolbutamide.
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 voriconazole (Vfend): your liver uses an enzyme called CYP2C9 to help clear it. In lab dish studies, ginkgo appears to slow that enzyme down a bit. If that happened in your body, voriconazole could build up and you might notice more of its usual side effects, like visual changes (blurry vision or light sensitivity), nausea, headache, or rising liver enzymes.

That said, this is theoretical. The evidence is only test-tube data, and human studies show ginkgo doesn't meaningfully change other CYP2C9 drugs. So a real-world problem is unlikely. Voriconazole levels can vary a lot from person to person, so it's still smart to mention any ginkgo to your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Yale SH, Glurich I. Analysis of the inhibitory potential of Ginkgo biloba, Echinacea purpurea, and Serenoa repens on the metabolic activity of cytochrome P450 3A4, 2D6, and 2C9. J Altern Complement Med 2005;11:433-9.
  2. Gaudineau C, Beckerman R, Welbourn S, Auclair K. Inhibition of human P450 enzymes by multiple constituents of the Ginkgo biloba extract. Biochem Biophys Res Comm 2004;318:1072–8. PubMed
  3. Mohutsky MA, Anderson GD, Miller JW, Elmer GW. Ginkgo biloba: evaluation of CYP2C9 drug interactions in vitro and in vivo. Am J Ther 2006;13:24-31. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 3

Voriconazole also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, ginkgo might decrease levels of drugs metabolized by CYP3A4.
There is conflicting evidence about whether ginkgo induces or inhibits CYP3A4. Ginkgo does not appear to affect hepatic CYP3A4. However, it is not known if ginkgo affects intestinal CYP3A4. Preliminary clinical research suggests that taking ginkgo does not significantly affect levels of donepezil, lopinavir, or ritonavir, which are all CYP3A4 substrates. Other clinical research also suggests ginkgo does not significantly affect CYP3A4 activity. However, there are two case reports of decreased efavirenz concentrations and increased viral load in patients taking ginkgo. It is suspected that terpenoids from the ginkgo extract reduced drug levels by inducing cytochrome P450 3A4 (CYP3A4).
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 connection: your body partly clears voriconazole using a liver enzyme called CYP3A4. There's a theory that ginkgo might speed that enzyme up. If that happened, your voriconazole could get broken down a little faster, leaving lower levels in your blood. With an antifungal, weaker levels are the real worry, because the medicine might not fully knock out a serious infection like aspergillosis or candidemia.

That said, the evidence here is genuinely shaky. Studies disagree, and most found ginkgo had little effect on this enzyme. So this is more a theoretical caution than a proven problem. Since voriconazole treats dangerous infections where every bit of drug matters, please run any ginkgo use past your pharmacist or doctor first rather than guessing.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Gurley BJ, Gardner SF, Hubbard MA. Clinical assessment of potential cytochrome P450-mediated herb-drug interactions. AAPS Ann Mtg & Expo Indianapolis, IN: 2000; Oct 29 - Nov 2:presentation #3460.
  2. Galluzzi S, Zanetti O, Binetti G, et al. Coma in a patient with Alzheimer's disease taking low dose trazodone and Ginkgo biloba. J Neurol Neurosurg Psychiatry 2000;68:679-80. DOI
  3. Budzinski JW, Foster BC, Vandenhoek S, Arnason JT. An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures. Phytomedicine 2000;7:273-82. PubMed
  4. 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
  5. Yale SH, Glurich I. Analysis of the inhibitory potential of Ginkgo biloba, Echinacea purpurea, and Serenoa repens on the metabolic activity of cytochrome P450 3A4, 2D6, and 2C9. J Altern Complement Med 2005;11:433-9.
  6. Yasui-Furukori N, Furukori H, Kaneda A, et al. The effects of Ginkgo biloba extracts on the pharmacokinetics and pharmacodynamics of donepezil. J Clin Pharmacol 2004;44:538-42.
  7. Markowitz JS, Donovan JL, Lindsay DeVane C, et al. Multiple-dose administration of Ginkgo biloba did not affect cytochrome P-450 2D6 or 3A4 activity in normal volunteers. J Clin Psychopharmacol 2003;23:576-81. PubMed
  8. Wiegman DJ, Brinkman K, Franssen EJ. Interaction of Ginkgo biloba with efavirenz. AIDS 2009;23:1184-5. PubMed
  9. Naccarato M, Yoong D, Gough K. A potential drug-herbal interaction between Ginkgo biloba and efavirenz. J Int Assoc Physicians AIDS Care (Chic). 2012;11(2):98-100. doi: 10.1177/1545109711435364. Epub 2012 Feb 9.
  10. Robertson, S. M., Davey, R. T., Voell, J., Formentini, E., Alfaro, R. M., and Penzak, S. R. Effect of Ginkgo biloba extract on lopinavir, midazolam and fexofenadine pharmacokinetics in healthy subjects. Curr Med Res Opin 2008;24(2):591-599. PubMed
  11. Penzak, S. R., Busse, K. H., Robertson, S. M., Formentini, E., Alfaro, R. M., and Davey, R. T., Jr. Limitations of using a single postdose midazolam concentration to predict CYP3A-mediated drug interactions. J Clin Pharmacol 2008;48(6):671-680. PubMed
  12. 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
  13. Bai J, Zhang C. Metabolic interaction between biflavonoids in Ginkgo biloba leaves and tacrolimus. Biopharm Drug Dispos 2023;44(2):157-164.

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

Ginkgo Also Interacts With Other Medications

Ginkgo has 1 major, 1,264 moderate known drug interactions in our database — the Voriconazole one above is among them. If you take anything else, check it against the full list below.

Major 1 Moderate 1,264 No known interaction 1,565 (incl. Voriconazole)
Taking anything else?

Check Another of Your Medications Against Ginkgo

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

From our Q&A

Questions About Ginkgo or Voriconazole

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

This page covers Ginkgo only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Voriconazole page lists 205 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).

By severity: 6 major · 159 moderate · 40 minor.

From our pharmacist’s overview on the Voriconazole page

“Voriconazole (Vfend) is a heavy-hitter antifungal, usually prescribed for dangerous infections like invasive aspergillosis, and its list of 205 interacting supplements includes six rated major, enough that anyone on this drug should read those entries before touching a supplement bottle. Most interactions run through the liver enzymes…”

Reviewed by 2 · Jul 18, 2026

Open the Voriconazole interaction page

One more smart check

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

We hold 4,399 real supplement products containing Ginkgo, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Ginkgo. Your product may carry other ingredients that interact with Voriconazole too, on top of Ginkgo — 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 Ginkgo and Voriconazole 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 Ginkgo
Top 5%

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

29 days ago today
Medication Voriconazole
Steady interest

#1,862 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 Ginkgo

What is Ginkgo?

Ginkgo
  • Memory and cognitive support
  • Age-related mental decline
  • Circulation problems
  • Tinnitus (ringing in the ears)
  • Dizziness or vertigo

Ginkgo is one of the world's most popular herbal supplements, mostly taken to support memory and circulation. The evidence for these uses is mixed and generally weak, and it is not proven to prevent memory loss or dementia. It is usually well tolerated in healthy adults, but it can thin the blood, so talk to your pharmacist or doctor before using it.

Read the full Ginkgo monograph & all interactions
Medication

About Voriconazole

What Is Voriconazole Used For?

Brand name: Vfend

Voriconazole treats several serious fungal infections. Across all available forms — tablets, oral suspension, and intravenous (IV) injection — it is used for invasive aspergillosis (a dangerous mold infection), candidemia (Candida fungus in the bloodstream) in patients who are not neutropenic (not severely low on white blood cells), other deep-tissue Candida infections, and serious infections caused by Scedosporium apiospermum or Fusarium species in patients who cannot tolerate or have not responded to other antifungal treatments.

Esophageal candidiasis (a Candida infection of the esophagus, the swallowing tube) is also an approved use for most formulations. Note on the oral tablet form (generic voriconazole tablets): that specific tablet formulation is approved for patients aged 12 to 14 years weighing at least 50 kg, and all patients 15 years and older — not for younger or smaller children. The oral suspension and the IV injection are approved for patients 2 years and older for most of these conditions.

See full Voriconazole drug information
Keep checking

Other Drugs & Ginkgo

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

1Major
1,264Moderate
0Minor
1,564No known interaction
1 Major 1,264 Moderate 1,564 No interaction
Major

1 interaction

Moderate

1,264 interactions

Showing 60 of 1,264 moderate interactions — see all 1,264 on the Ginkgo page.

No interaction 1,564 drugs checked — show the list

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

Showing the 60 most looked-up of 1,564 medications checked with no known interaction — see the full Ginkgo list.

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

Can you take Ginkgo with Voriconazole?
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 3 interactions listed for Ginkgo and Voriconazole?
Voriconazole belongs to more than one drug category, and Ginkgo 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 Ginkgo and Voriconazole 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 Voriconazole and Ginkgo?

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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.