Drug & supplement interaction

Turkey Tail Mushroom + Phenobarbital, Phenytoin

Phenobarbital, Phenytoin brand name: Dilantin with PB.

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

Turkey Tail Mushroom has a minor interaction with Phenobarbital, Phenytoin. Theoretically, the polysaccharide peptide (PSP) component of turkey tail mushroom might inhibit CYP2C9.

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

Turkey Tail Mushroom and Phenobarbital, Phenytoin

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

Minor

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

Why this applies to Phenobarbital, Phenytoin

Phenobarbital, Phenytoin falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES — the group Turkey Tail Mushroom interacts with.

Theoretically, the polysaccharide peptide (PSP) component of turkey tail mushroom might inhibit CYP2C9.
Laboratory research suggests that the PSP component of turkey tail mushroom dose-dependently inhibits CYP2C9. Theoretically, taking PSP with drugs metabolized by CYP2C9 might increase drug levels and the risk of adverse effects. However, this has not been reported in humans.
Severity Minor 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: phenytoin is partly cleared by a liver enzyme called CYP2C9, and lab studies hint that the PSP compound in turkey tail might slow that enzyme down. If that happened in real life, your phenytoin could build up a bit. Because phenytoin has a narrow safety window, even small jumps can tip you into side effects like dizziness, unsteady walking, slurred speech, double vision, or drowsiness.

That said, this is purely theoretical right now. It comes from test-tube research, not from people, so it's rated minor. I wouldn't lose sleep over it, but since phenytoin levels are touchy, mention the turkey tail to your pharmacist or doctor so they can keep an eye on your levels if needed.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Yeung JH and Or PM. Polysaccharide peptides from Coriolus versicolor competitively inhibit tolbutamide 4-hydroxylation in specific human CYP2C9 isoform and pooled human liver microsomes. Phytomedicine 2011;18(13):1170-5. 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

Turkey Tail Mushroom Also Interacts With Other Medications

Turkey Tail Mushroom has 88 moderate, 99 minor known drug interactions in our database — the Phenobarbital, Phenytoin one above is one of them. If you take anything else, check it against the full list below.

Moderate 88 Minor 99 No known interaction 2,643 (incl. Phenobarbital, Phenytoin)
Taking anything else?

Check Another of Your Medications Against Turkey Tail Mushroom

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

Everything else you take

See Every Supplement That Interacts With Phenobarbital, Phenytoin

This page covers Turkey Tail Mushroom only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phenobarbital, Phenytoin page lists 229 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Kava (major).

By severity: 9 major · 192 moderate · 28 minor.

From our pharmacist’s overview on the Phenobarbital, Phenytoin page

“If your seizure medicine is the phenobarbital and phenytoin combination (Dilantin with PB), read this list carefully before you add any supplement. Nine of the 229 entries rate major, and most of the risk runs through two channels.”

Reviewed by 2 · Jul 18, 2026

Open the Phenobarbital, Phenytoin interaction page

How much people look this up

Where Turkey Tail Mushroom and Phenobarbital, Phenytoin 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 Turkey Tail Mushroom
Top half

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

29 days ago today
Medication Phenobarbital, Phenytoin
Top 25%

#386 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 Turkey Tail Mushroom

What is Turkey Tail Mushroom?

Turkey Tail Mushroom
  • Immune support
  • Used alongside cancer care
  • Gut and digestive health
  • General wellness and energy
  • Antioxidant support

Turkey tail is a woodland mushroom rich in polysaccharides like beta-glucans, and it is mainly used to support the immune system. Some of its purified extracts (PSK and PSP) have been studied as add-on treatments alongside conventional cancer therapy in Asia, but evidence for everyday supplement use is limited. It is generally well tolerated, but talk to your pharmacist or doctor before using it, especially if you have a health condition or take other medicines.

Read the full Turkey Tail Mushroom monograph & all interactions
Keep checking

Other Drugs & Turkey Tail Mushroom

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

0Major
88Moderate
99Minor
2,642No known interaction
88 Moderate 99 Minor 2,642 No interaction
Moderate

88 interactions

Showing 60 of 88 moderate interactions — see all 88 on the Turkey Tail Mushroom page.

Minor

99 interactions

Showing 60 of 99 minor interactions — see all 99 on the Turkey Tail Mushroom page.

No interaction 2,642 drugs checked — show the list

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

Showing the 60 most looked-up of 2,642 medications checked with no known interaction — see the full Turkey Tail Mushroom list.

See the full Turkey Tail Mushroom interactions page
See every supplement checked against Phenobarbital, Phenytoin, 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
Turkey Tail Mushroom monograph › Uses, safety, and every drug interaction in one place Phenobarbital, Phenytoin supplement interactions › Every supplement checked against Phenobarbital, Phenytoin, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Turkey Tail Mushroom and Phenobarbital, Phenytoin Together: Common Questions

Can you take Turkey Tail Mushroom with Phenobarbital, Phenytoin?
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 Turkey Tail Mushroom and Phenobarbital, Phenytoin 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

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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.