Drug & supplement interaction

Cordyceps + Fostamatinib

Fostamatinib brand name: Tavalisse.

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

Cordyceps has a moderate interaction with Fostamatinib. Theoretically, concurrent use of cordyceps might interfere with immunosuppressive therapy.

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

Cordyceps and Fostamatinib

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

Moderate

IMMUNOSUPPRESSANTS

Why this applies to Fostamatinib

Fostamatinib falls under IMMUNOSUPPRESSANTS — the group Cordyceps interacts with.

Theoretically, concurrent use of cordyceps might interfere with immunosuppressive therapy.
Animal and in vitro research suggests that cordyceps stimulates the immune system. However, limited clinical research suggests that taking cordyceps may lower the necessary therapeutic dose of the immunosuppressant cyclosporine, which suggests that cordyceps may have an immunosuppressive effect.
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 honest picture with cordyceps and Tavalisse (fostamatinib). The concern on file is that cordyceps might tug on the immune system, which could in theory clash with medicines that work on immune activity. But this is mostly based on lab and animal studies, plus a little human data with a different drug (cyclosporine), so it's a theoretical worry, not something clearly proven for fostamatinib.

Cordyceps may actually nudge the immune system in either direction depending on the study, so the real-world effect on your platelet count is hard to predict. Since fostamatinib is treating low platelets, anything that quietly shifts how it works matters. Please loop in your pharmacist or doctor before adding cordyceps so they can keep an eye on your platelet numbers, bruising, or bleeding.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Zhu JS, Halpern GM, Jones K. The scientific rediscovery of an ancient Chinese herbal medicine: Cordyceps sinensis: part I. J Altern Complement Med 1998;4:289-303.
  2. Zhu JS, Halpern GM, Jones K. The scientific rediscovery of a precious ancient Chinese herbal regimen: Cordyceps sinensis: part II. J Altern Complement Med 1998;4:429-57.
  3. Chen YJ, Shiao MS, Lee SS, Wang SY. Effect of Cordyceps sinensis on the proliferation and differentiation of human leukemic U937 cells. Life Sci 1997;60:2349-59. PubMed
  4. Chen GZ, Chen GL, Sun T, et al. Effects of Cordyceps sinensis on murine T lymphocyte subsets. Chin Med J (English) 1991;104:4-8.
  5. Zhu XY, Yu HY. [Immunosuppressive effect of cultured Cordyceps sinensis on cellular immune response]. Chung Hsi I Chieh Ho Tsa Chih 1990;10:485-7, 454.
  6. Hong T, Zhang M, Fan J. Cordyceps sinensis (a traditional Chinese medicine) for kidney transplant recipients (Review). Cochrane Database Syst Rev. 2015;(10):CD009698. doi: 10.1002/14651858.CD009698.pub2.

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

Cordyceps Also Interacts With Other Medications

Cordyceps has 240 moderate, 8 minor known drug interactions in our database — the Fostamatinib one above is one of them. If you take anything else, check it against the full list below.

Moderate 240 Minor 8 No known interaction 2,582 (incl. Fostamatinib)
Taking anything else?

Check Another of Your Medications Against Cordyceps

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

Everything else you take

See Every Supplement That Interacts With Fostamatinib

This page covers Cordyceps only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fostamatinib page lists 209 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 · 167 moderate · 36 minor.

From our pharmacist’s overview on the Fostamatinib page

“I would treat the supplement list for fostamatinib (Tavalisse), a medicine that raises platelet counts in chronic immune thrombocytopenia, with real care. Most of what shows up here involves CYP3A4, the liver enzyme that clears fostamatinib, so grapefruit can drive its blood level up while St.”

Reviewed by 2 · Jul 18, 2026

Open the Fostamatinib interaction page

One more smart check

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

We hold 2,140 real supplement products containing Cordyceps, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cordyceps. Your product may carry other ingredients that interact with Fostamatinib too, on top of Cordyceps — 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 Cordyceps and Fostamatinib 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 Cordyceps
Top 10%

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

29 days ago today
Medication Fostamatinib
Steady interest

#1,806 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 Cordyceps

What is Cordyceps?

Cordyceps
  • Fatigue and low energy
  • Athletic performance and stamina
  • Respiratory and lung support
  • Immune support
  • Kidney health support
  • General wellness/anti-aging

Cordyceps is a fungus used in traditional Chinese medicine for energy, exercise performance, and lung and immune support. Human research is limited and mostly low quality, so its benefits are not well proven. It appears generally well tolerated in the short term, but quality varies and it should be avoided in pregnancy and breastfeeding due to lack of safety data.

Read the full Cordyceps monograph & all interactions
Medication

About Fostamatinib

What Is Fostamatinib Used For?

Brand name: Tavalisse

Tavalisse (fostamatinib) is used to treat thrombocytopenia — dangerously low platelet counts — in adults with chronic immune thrombocytopenia (ITP). It is specifically for people whose platelet counts have not improved enough with at least one earlier ITP treatment.

The goal is to raise platelet counts high enough to reduce the risk of serious bleeding. If platelet counts do not respond sufficiently after 12 weeks, the medication is typically stopped.

See full Fostamatinib drug information
Keep checking

Other Drugs & Cordyceps

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

0Major
240Moderate
8Minor
2,581No known interaction
240 Moderate 8 Minor 2,581 No interaction
Moderate

240 interactions

Showing 60 of 240 moderate interactions — see all 240 on the Cordyceps page.

Minor

8 interactions

No interaction 2,581 drugs checked — show the list

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

Showing the 60 most looked-up of 2,581 medications checked with no known interaction — see the full Cordyceps list.

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

Can you take Cordyceps with Fostamatinib?
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 Cordyceps and Fostamatinib 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 Fostamatinib and Cordyceps?

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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.