Drug & supplement interaction

Ginkgo + Theophylline

Theophylline brand names: T-Phyl, Duraphyl, Aerolate JR, Aerolate SR, Theo-Dur, and others.

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

Theophylline falls into 2 drug categories that Ginkgo can interact with; the most serious is rated moderate. Theoretically, taking ginkgo with drugs that lower the seizure threshold might increase the risk for convulsions.

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

Ginkgo and Theophylline

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

Why Are There 2 Interactions?

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

Moderate

SEIZURE THRESHOLD LOWERING DRUGS

1 of 2

Why this applies to Theophylline

Theophylline falls under SEIZURE THRESHOLD LOWERING DRUGS — the group Ginkgo interacts with.

Theoretically, taking ginkgo with drugs that lower the seizure threshold might increase the risk for convulsions.
Ginkgo seeds contain ginkgotoxin. Large amounts of ginkgotoxin can cause neurotoxicity and seizure. Ginkgotoxin is present in much larger amounts in ginkgo seeds than leaves. Ginkgo leaf extract contains trace amounts of ginkgotoxin. The amount of ginkgotoxin in ginkgo leaf and leaf extract seems unlikely to cause toxicity. However, there are anecdotal reports of seizure occurring after use of ginkgo leaf both in patients without a history of seizure disorder and in those with previously well-controlled epilepsy.
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 connection worth knowing about. Theophylline can, on its own, make the brain a little more prone to seizures, especially if your blood levels run high (it's a drug we watch closely because the safe range is narrow). Ginkgo can add to that picture. The seed of the ginkgo plant contains a compound called ginkgotoxin that may lower the seizure threshold, meaning it could nudge your risk of a convulsion upward.

That said, the leaf extract used in most supplements has only trace amounts of ginkgotoxin, and this concern is mostly theoretical, backed by a few anecdotal reports rather than strong studies. Still, since both can affect seizure risk, it's a smart idea to run this combo by your pharmacist or doctor before adding ginkgo.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Gregory PJ. Seizure associated with Ginkgo biloba? Ann Intern Med 2001;134:344.
  2. Granger AS. Ginkgo biloba precipitating epileptic seizures. Age Ageing 2001;30:523-5. PubMed
  3. Miwa H, Iijima M, Tanaka S, Mizuno Y. Generalized convulsions after consuming a large amount of gingko nuts. Epilepsia 2001;42:280-1. DOI
  4. Arenz A, Kelin M, Flehe K, et al. Occurrence of neurotoxic 4'-O-methylpyridoxine in ginkgo biloba leaves, ginkgo medications and Japanese ginkgo food. Planta Med 1996;62:548-51.
  5. Kupiec T, Raj V. Fatal seizures due to potential herb-drug interactions with Ginkgo biloba. J Anal Toxicol 2005:755-8. PubMed
Moderate

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

2 of 2

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

Theoretically, ginkgo might increase levels of drugs metabolized by CYP1A2.
Laboratory research suggests that ginkgo leaf extract can mildly inhibit CYP1A2 enzymes. However, clinical research suggests ginkgo might not affect CYP1A2. Until more is known, use ginkgo cautiously in patients taking drugs metabolized by these enzymes.
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 gist with these two together. Your body clears theophylline mainly through a liver enzyme called CYP1A2. Lab studies hint that ginkgo might slow that enzyme down a little, which in theory could let theophylline build up in your blood. Since theophylline has a narrow safety window, even a modest rise can matter, possibly causing nausea, a racing or pounding heartbeat, jitteriness, trouble sleeping, or in larger amounts, tremors.

That said, the human studies we have suggest ginkgo probably doesn't change theophylline levels much, so this is more of a theoretical concern than a proven problem. I wouldn't panic, but please loop in your pharmacist or doctor before adding ginkgo so they can keep an eye on how you feel.

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

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 Theophylline 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. Theophylline)
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 Theophylline

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 Theophylline, 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 Theophylline

This page covers Ginkgo only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Theophylline page lists 126 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Sida Cordifolia (major), Adrafinil (moderate) and African Wild Potato (moderate).

By severity: 3 major · 89 moderate · 34 minor.

From our pharmacist’s overview on the Theophylline page

“Stop ephedra before anything else if you take theophylline (Theo-Dur, Slo-Bid, and others) for asthma or COPD. Both are stimulants, and together they raise the risk of serious heart and nervous system effects; Sida cordifolia, an herb that contains ephedrine, carries the same major rating.”

Reviewed by 2 · Jul 18, 2026

Open the Theophylline 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 Theophylline 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 Theophylline 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%

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

29 days ago today
Medication Theophylline
Steady interest

#1,906 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 Theophylline

What Is Theophylline Used For?

Brand names: T-Phyl, Duraphyl, Aerolate JR, Aerolate SR, Theo-Dur, Slo-Bid, Theo-24, Uniphyl, Slo-phyllin Gyrocaps, Theolair, Theolair SR, Quibron-T/SR, Quibron-T, Aerolate III, Theo-X, Bronkodyl, Theoclear LA-130, Constant-T, Theoclear LA-260, Elixophyllin, Theovent, Theobid Jr Duracap, Respbid, Theobid Duracap

Theophylline — available as extended-release capsules (Theo-24), extended-release tablets, and oral solution (Elixophyllin) — is used to treat symptoms and reversible airflow obstruction caused by chronic asthma, emphysema, and chronic bronchitis.

All supported formulations share these indications. Theophylline is intended for patients with ongoing or recurring symptoms, not for sudden (acute) breathing attacks, which need faster-acting treatments.

See full Theophylline 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 Theophylline, 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 Theophylline supplement interactions › Every supplement checked against Theophylline, ranked by severity Theophylline 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 Theophylline Together: Common Questions

Can you take Ginkgo with Theophylline?
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 Ginkgo and Theophylline?
Theophylline 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 Theophylline 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

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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.