Drug & supplement interaction

Shiitake Mushroom + Fluoxetine

Fluoxetine brand names: Prozac, Sarafem.

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

Shiitake Mushroom has a moderate interaction with Fluoxetine. Theoretically, shiitake mushroom might decrease levels of drugs metabolized by CYP2D6.

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

Shiitake Mushroom and Fluoxetine

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

Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

Why this applies to Fluoxetine

Fluoxetine falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Shiitake Mushroom interacts with.

Theoretically, shiitake mushroom might decrease levels of drugs metabolized by CYP2D6.
In vitro studies suggest that the shiitake mushroom extract AHCC might induce the CYP2D6 enzyme. This effect has not been reported in humans.
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: your body uses an enzyme called CYP2D6 to help break down fluoxetine. Some lab studies hint that a concentrated shiitake extract (AHCC) might speed that enzyme up. If that happened, your fluoxetine could clear out a little faster, which in theory might make it work less well. For fluoxetine that could look like depression, anxiety, or OCD symptoms creeping back.

The honest part: this is only seen in test-tube research, not in real people, so the concern is theoretical. Eating shiitake as a normal food is very unlikely to matter. If you're thinking about taking concentrated shiitake or AHCC supplements, just run it by your pharmacist or doctor first so they can keep an eye on how you're feeling.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mach, C. M., Fugii, H., Wakame, K., and Smith, J. Evaluation of active hexose correlated compound hepatic metabolism and potential for drug interactions with chemotherapy agents. J Soc Integr.Oncol. 2008;6(3):105-109.
  2. Smith, J. A., Hunter, R. J., Fujii, H., Wakame, K., and Wolf, J. Defining Synergistic Activity ofthe Combination of Active Hexose Correlated Compound (AHCC) with Liposomal Doxorubicin (Doxil). Presented at the 18th International Congress on Nutrition and

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

Shiitake Mushroom Also Interacts With Other Medications

Shiitake Mushroom has 311 moderate known drug interactions in our database — the Fluoxetine one above is one of them. If you take anything else, check it against the full list below.

Moderate 311 No known interaction 2,519 (incl. Fluoxetine)
Taking anything else?

Check Another of Your Medications Against Shiitake Mushroom

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

From our Q&A

Questions About Shiitake Mushroom or Fluoxetine

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

This page covers Shiitake Mushroom only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fluoxetine page lists 163 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 8 major · 127 moderate · 28 minor.

From our pharmacist’s overview on the Fluoxetine page

“Grapefruit is the surprise at the top of fluoxetine's (Prozac) supplement list. In large amounts it can stretch the QT interval, the electrical pause between heartbeats, and fluoxetine, a widely prescribed antidepressant, can do the same, raising the odds of a dangerous rhythm.”

Reviewed by 2 · Jul 18, 2026

Open the Fluoxetine interaction page

One more smart check

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

We hold 1,613 real supplement products containing Shiitake Mushroom, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Shiitake Mushroom. Your product may carry other ingredients that interact with Fluoxetine too, on top of Shiitake Mushroom — 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 Shiitake Mushroom and Fluoxetine 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 Shiitake Mushroom
Top 25%

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

29 days ago today
Medication Fluoxetine
Top 1%

#28 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 Shiitake Mushroom

What is Shiitake Mushroom?

  • Immune support
  • General wellness and nutrition
  • Cholesterol and heart health
  • Adjunct in cancer care (lentinan, AHCC)
  • Antioxidant support

Shiitake is a popular edible mushroom that is nutritious and safe to eat as food for most people. Some of its extracts (like lentinan and AHCC) have been studied as immune support, mainly alongside cancer treatment, but evidence for most supplement uses is limited. Talk with your pharmacist or doctor before using concentrated shiitake supplements.

Read the full Shiitake Mushroom monograph & all interactions
Medication

About Fluoxetine

What Is Fluoxetine Used For?

Brand names: Prozac, Sarafem

Fluoxetine is approved to treat four conditions: major depressive disorder (MDD), obsessive-compulsive disorder (OCD), bulimia nervosa (a binge-eating and purging disorder), and panic disorder — with or without agoraphobia (fear of situations that feel hard to escape).

It works for adults across all four conditions, and for children and teens with depression (ages 8–18) and OCD (ages 7–17).

See full Fluoxetine drug information
Keep checking

Other Drugs & Shiitake Mushroom

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

0Major
311Moderate
0Minor
2,518No known interaction
311 Moderate 2,518 No interaction
Moderate

311 interactions

Showing 60 of 311 moderate interactions — see all 311 on the Shiitake Mushroom page.

No interaction 2,518 drugs checked — show the list

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

Showing the 60 most looked-up of 2,518 medications checked with no known interaction — see the full Shiitake Mushroom list.

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

Can you take Shiitake Mushroom with Fluoxetine?
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 Shiitake Mushroom and Fluoxetine 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 Fluoxetine and Shiitake Mushroom?

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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.