Drug & supplement interaction

Cordyceps + Famciclovir

Famciclovir brand name: Famvir.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 27, 2026
The bottom line No known interaction

We found no known interaction between Cordyceps and Famciclovir in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Cordyceps and Famciclovir

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Famciclovir and Cordyceps in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Cordyceps safety at a glance

Cordyceps overall Use caution Generally well tolerated short-term, but evidence is limited and product quality varies widely.
Pregnancy Avoid Not enough safety data, so it is best avoided during pregnancy.
Breastfeeding Avoid Not enough safety data, so it is best avoided while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Famciclovir and Cordyceps? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Famciclovir

Interactions in our licensed database are recorded against drug classes, not just single drug names. Famciclovir is filed under a single classification — oral drugs. Cordyceps has documented interactions with 3 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate), immunosuppressants (moderate) and testosterone (minor) — and none of Famciclovir’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Cordyceps Does Interact With Other Medications

Cordyceps has 241 moderate, 8 minor known drug interactions in our database — Famciclovir isn’t one of them. If you take anything else, check it against the full list below.

Moderate 241 Minor 8 No known interaction 2,581 (incl. Famciclovir)
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.

What to actually watch for

No Interaction Found — But Data Suggests Cordyceps and Famciclovir May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

  • Yellowing of the skin or eyes / Liver problems Worth acting on Additional detail

    Cordyceps

    “There is a case report of acute cholestatic hepatitis probably associated with the use of a product containing cordyceps. The 64-year-old male was asymptomatic except for jaundice and laboratory markers and recovered once the supplement was stopped. However, it is unclear whether the hepatitis is associated with the cordyceps or with an unknown contaminant.”

    Cordyceps · Natural Medicines adverse-effect record, reported in hepatitis.

    1 source cited
    1. 109704. Thurian D, Montani M, Stickel F. Drug-induced, mixed-type hepatitis following ingestion of Cordyceps sinensis. Int J Clin Pharmacol Ther 2022;60(2):115-120. PubMed

    Famciclovir

    Listed in the ADVERSE REACTIONS section of the FDA label for Famciclovir. Read the label on DailyMed ›

  • Diarrhea reported in 6.6% of FDA reports for Famciclovir Additional detail

    Cordyceps

    “Orally, cordyceps has been associated with diarrhea, constipation, abdominal discomfort, dry mouth, and throat discomfort in clinical research. However, these events were uncommon, and in some cases symptoms could be reduced by taking cordyceps after eating.”

    Cordyceps · Natural Medicines adverse-effect record, reported in constipation.

    3 sources cited
    1. 92829. Zhang HW, Lin ZX, Tung YS, Kwan TH, Mok CK, Leung C, Chan LS. Cordyceps sinensis (a traditional Chinese medicine) for treating chronic kidney disease (Review). Cochrane Database Syst Rev. 2014;(12):CD008353. doi: 10.1002/14651858.CD008353.pub2. PubMed
    2. 105076. Bee Yean O, Zoriah A. Efficacy of Cordyceps sinensis as an adjunctive treatment in hemodialysis patients: a systematic review and Meta-analysis. J Tradit Chin Med. 2019;39(1):1-14.
    3. 109705. Yu X, Mao Y, Shergis JL, et al. Effectiveness and safety of oral Cordyceps sinensis on stable COPD of GOLD stages 2-3: Systematic review and meta-analysis. Evid Based Complement Alternat Med. 2019;2019:4903671.

    Famciclovir

    Listed in the ADVERSE REACTIONS section of the FDA label for Famciclovir, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for Cordyceps but not commonly for Famciclovir: stomach upset, reduced appetite, constipation and dry mouth.

Effects for Famciclovir come from the ADVERSE REACTIONS section of its FDA label; effects for Cordyceps come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 2,753 voluntary FDA FAERS reports for Famciclovir that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

From our Q&A

Questions About Cordyceps or Famciclovir

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

This page covers Cordyceps only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Famciclovir page lists 17 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).

By severity: 1 major · 7 moderate · 9 minor.

From our pharmacist’s overview on the Famciclovir page

“Famciclovir (Famvir) treats herpes infections like shingles and cold sores, and it only works if enough of the drug gets absorbed from your gut, which is exactly where every supplement on this list can interfere. The entry I would take most seriously is activated charcoal, the lone major-rated interaction, because charcoal binds medica…”

Reviewed by 2 · Jul 18, 2026

Open the Famciclovir 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. Even though Cordyceps itself has no known interaction with Famciclovir, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Cordyceps and Famciclovir 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%

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

29 days ago today
Medication Famciclovir
Top half

#1,326 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Cordyceps reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 27, 2026. The Cordyceps and Famciclovir records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
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.

Ophiocordyceps sinensis · Ophiocordycipitaceae · Whole fungus (fruiting body and mycelium), often grown in culture as the Cs-4 strain · Capsules, tablets, powders, extracts, teas, and tinctures

An interaction check asks whether these two react with each other — it does not ask whether Cordyceps is a good idea for someone in your situation. Here is what our Cordyceps record says about it on its own.

Cordyceps: dosing

There is no official or standardized dose for cordyceps. Doses used in studies have varied widely depending on the product, species, and extract type.The best approach is to follow the directions on the product label and not exceed the recommended amount.

From our Cordyceps monograph — the full record covers uses, side effects and every documented interaction.

Read the full Cordyceps monograph & all interactions
Medication

About Famciclovir

What Is Famciclovir Used For?

Brand name: Famvir

Famciclovir tablets are used in adults to treat recurrent cold sores (herpes labialis), recurrent episodes of genital herpes, and shingles (herpes zoster). For genital herpes, it can also be taken daily as suppressive therapy to reduce how often outbreaks happen.

In adults living with HIV, famciclovir is used to treat recurrent episodes of orolabial herpes (cold sores) or genital herpes. It is not approved for a first-ever genital herpes outbreak, herpes affecting the eye (ophthalmic zoster), or for use in children.

Most-Reported Side Effects for Famciclovir

From FAERS, the FDA’s public side-effect reporting system (2,753 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 191 reports
Diarrhea 183 reports
Nausea 153 reports
Headache 142 reports
Rash 114 reports
See full Famciclovir 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
241Moderate
8Minor
2,580No known interaction
241 Moderate 8 Minor 2,580 No interaction
Moderate

241 interactions

Showing 60 of 241 moderate interactions — see all 241 on the Cordyceps page.

Minor

8 interactions

No interaction 2,580 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 2,580 medications checked with no known interaction — see the full Cordyceps list.

See the full Cordyceps interactions page
See every supplement checked against Famciclovir, ranked by severity
Evidence & sources

Cordyceps References

The 14 references that drive our Cordyceps monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  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. Zhao Y. [Inhibitory effects of alcoholic extract of Cordyceps sinensis on abdominal aortic thrombus formation in rabbits]. Chung Hua I Hsueh Tsa Chih (Taipei) 1991;71:612-5, 42.
  5. 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.
  6. 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.
  7. Hsu, C. C., Huang, Y. L., Tsai, S. J., Sheu, C. C., and Huang, B. M. In vivo and in vitro stimulatory effects of Cordyceps sinensis on testosterone production in mouse Leydig cells. Life Sci 9-5-2003;73(16):2127-2136. PubMed
  8. Ikumoto, T., Sasaki, S., Namba, H., Toyama, R., Moritoki, H., and Mouri, T. [Physiologically active compounds in the extracts from tochukaso and cultured mycelia of Cordyceps and Isaria]. Yakugaku Zasshi 1991;111(9):504-509. PubMed
  9. Wu, T. N., Yang, K. C., Wang, C. M., Lai, J. S., Ko, K. N., Chang, P. Y., and Liou, S. H. Lead poisoning caused by contaminated Cordyceps, a Chinese herbal medicine: two case reports. Sci.Total Environ. 4-5-1996;182(1-3):193-195. PubMed
  10. 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.
  11. Zhang HW, Lin ZX, Tung YS, Kwan TH, Mok CK, Leung C, Chan LS. Cordyceps sinensis (a traditional Chinese medicine) for treating chronic kidney disease (Review). Cochrane Database Syst Rev. 2014;(12):CD008353. doi: 10.1002/14651858.CD008353.pub2. PubMed
  12. Bee Yean O, Zoriah A. Efficacy of Cordyceps sinensis as an adjunctive treatment in hemodialysis patients: a systematic review and Meta-analysis. J Tradit Chin Med. 2019;39(1):1-14.
  13. Thurian D, Montani M, Stickel F. Drug-induced, mixed-type hepatitis following ingestion of Cordyceps sinensis. Int J Clin Pharmacol Ther 2022;60(2):115-120. PubMed
  14. Yu X, Mao Y, Shergis JL, et al. Effectiveness and safety of oral Cordyceps sinensis on stable COPD of GOLD stages 2-3: Systematic review and meta-analysis. Evid Based Complement Alternat Med. 2019;2019:4903671.

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Cordyceps and Famciclovir Together: Common Questions

Is it safe to take Cordyceps with Famciclovir?
We do not list a known interaction between Cordyceps and Famciclovir. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Cordyceps and Famciclovir have any of the same side effects?
Yes — our sources link each of them separately to 3 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
How was the Cordyceps and Famciclovir combination checked?
Interactions in our licensed database are recorded against drug classes. Famciclovir is filed under 1 classification, and Cordyceps has documented interactions with 3 drug classes — none of Famciclovir's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Cordyceps interact with any other medications?
Yes. Cordyceps has 249 documented drug interactions in our database — Famciclovir is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Famciclovir interact with any supplements?
Yes. Famciclovir has documented interactions with 17 supplements in our database — Cordyceps is not one of them. The Famciclovir interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Cordyceps monograph Uses, safety profile, and every drug interaction in one place Famciclovir drug information The full plain-English guide to this medication Famciclovir supplement interactions Every supplement checked against Famciclovir, 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 References The 14 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Famciclovir 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.