Drug & supplement interaction

Cordyceps + Fluorouracil (IV)

Fluorouracil (IV) brand name: Fluorouracil.

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

Cordyceps has a moderate interaction with Fluorouracil (IV). 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 Fluorouracil (IV)

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

Moderate

IMMUNOSUPPRESSANTS

Why this applies to Fluorouracil (IV)

Fluorouracil (IV) 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 IV fluorouracil (5-FU). The concern on file comes from the idea that cordyceps may nudge the immune system, which could theoretically clash with medicines that calm or suppress immune activity. The trouble is, fluorouracil is a chemotherapy drug, not a true immunosuppressant in the way cyclosporine is, so this particular interaction doesn't map neatly onto it. The evidence here is also weak and mostly theoretical or from lab and animal studies.

What I'd stress is the bigger principle: chemo timing and dosing are finely tuned, and side effects like mouth sores, low blood counts, and stomach upset are serious. Please don't add cordyceps during 5-FU treatment without clearing it with your oncology team first.

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 Fluorouracil (IV) 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. Fluorouracil (IV))
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 Fluorouracil (IV)

This page covers Cordyceps only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fluorouracil (IV) page lists 59 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Active Hexose Correlated Compound (ahcc) (moderate), Alfalfa (moderate), American Ginseng (moderate), Andrographis (moderate) and Ashwagandha (moderate).

By severity: 58 moderate · 1 minor.

From our pharmacist’s overview on the Fluorouracil (IV) page

“Fluorouracil is an IV chemotherapy medicine, and the supplement list attached to it is manageable for most people once you see the single thread running through it. Nearly all 59 entries are herbs and extracts believed to stimulate the immune system, ashwagandha, astragalus, and medicinal mushroom products among them, and the concern i…”

Reviewed by 2 · Jul 18, 2026

Open the Fluorouracil (IV) 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 Fluorouracil (IV) 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 Fluorouracil (IV) 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%

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

29 days ago today
Medication Fluorouracil (IV)
Steady interest

#1,611 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
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 Fluorouracil (IV), 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 Fluorouracil (IV) supplement interactions › Every supplement checked against Fluorouracil (IV), 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 Cordyceps and Fluorouracil (IV) Together: Common Questions

Can you take Cordyceps with Fluorouracil (IV)?
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 Fluorouracil (IV) 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 Fluorouracil (IV) 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.