Drug & supplement interaction

Reishi Mushroom + Valacyclovir

Valacyclovir brand name: Valtrex.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Reishi Mushroom and Valacyclovir 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

Reishi Mushroom and Valacyclovir

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 Valacyclovir and Reishi Mushroom 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.

Reishi Mushroom safety at a glance

Reishi Mushroom overall Use caution Generally well tolerated short-term, but long-term safety is not well studied.
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 Valacyclovir and Reishi Mushroom? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Valacyclovir

Interactions in our licensed database are recorded against drug classes, not just single drug names. Valacyclovir is filed under 3 classifications — organic anion transporter 1 (oat1) substrates, seizure threshold lowering drugs, oral drugs. Reishi Mushroom has documented interactions with 3 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate), antidiabetes drugs (moderate) and antihypertensive drugs (moderate) — and none of Valacyclovir’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

Reishi Mushroom Does Interact With Other Medications

Reishi Mushroom has 375 moderate known drug interactions in our database — Valacyclovir isn’t one of them. If you take anything else, check it against the full list below.

Moderate 375 No known interaction 2,455 (incl. Valacyclovir)
Taking anything else?

Check Another of Your Medications Against Reishi Mushroom

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

What to actually watch for

No Interaction Found — But Data Suggests Reishi Mushroom and Valacyclovir 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. One of them is worth acting on rather than waiting out — marked below.

  • Liver problems Worth acting on Additional detail

    Reishi Mushroom

    “One case of hepatotoxicity and one case of fatal fulminant hepatitis have been reported in patients who had used reishi mushroom powder for 1-2 months. There is a case report of a 61-year-old male with hypereosinophilia associated with hepatic nodules following the use of reishi mushroom powder for about 2 months. Symptoms resolved after discontinuation of the product.”

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

    2 sources cited
    1. 70766. Wanmuang, H., Leopairut, J., Kositchaiwat, C., Wananukul, W., and Bunyaratvej, S. Fatal fulminant hepatitis associated with Ganoderma lucidum (Lingzhi) mushroom powder. J Med Assoc Thai. 2007;90(1):179-181.
    2. 108312. Kogure T, Koiwai A, Fukushi D, et al. Hypereosinophilia with hepatic nodule formation caused by Ganoderma lucidum. Intern Med 2021;60(24):3897-3903.

    Valacyclovir

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

  • Itching / A skin rash Additional detail

    Reishi Mushroom

    “Orally, reishi mushroom can cause itching, rash, and other skin reactions (12,5479).”

    Reishi Mushroom · Natural Medicines adverse-effect record, reported in pruritus.

    2 sources cited
    1. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
    2. 5479. Singh AB, Gupta SK, Pereira BM, Prakash D. Sensitization to Ganoderma lucidum in patients with respiratory allergy in India. Clin Exp Allergy 1995;25:440-7.

    Valacyclovir

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

  • Dizziness Additional detail

    Reishi Mushroom

    “Orally, reishi mushroom can cause dizziness. Other rare symptoms include insomnia and headache.”

    Reishi Mushroom · Natural Medicines adverse-effect record, reported in cluster headache.

    3 sources cited
    1. 91438. Zhao H, Zhang Q, Zhao L, Huang X, Wang J, Kang X. Spore Powder of Ganoderma lucidum Improves Cancer-Related Fatigue in Breast Cancer Patients Undergoing Endocrine Therapy: A Pilot Clinical Trial. Evid Based Complement Alternat Med. 2012;2012:809614.
    2. 70776. Chu, T. T., Benzie, I. F., Lam, C. W., Fok, B. S., Lee, K. K., and Tomlinson, B. Study of potential cardioprotective effects of Ganoderma lucidum (Lingzhi): results of a controlled human intervention trial. Br.J.Nutr. 2012;107(7):1017-1027.
    3. 70779. Jin, X., Ruiz, Beguerie J., Sze, D. M., and Chan, G. C. Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane.Database.Syst.Rev. 2012;6:CD007731.

    Valacyclovir

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

  • Diarrhea Additional detail

    Reishi Mushroom

    “Orally, reishi mushroom can cause dryness of the mouth, throat, or nasal cavity, nausea, stomach upset, and, more rarely, diarrhea (12,70779,91438,108309).”

    Reishi Mushroom · Natural Medicines adverse-effect record, reported in diarrhea.

    4 sources cited
    1. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
    2. 70779. Jin, X., Ruiz, Beguerie J., Sze, D. M., and Chan, G. C. Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane.Database.Syst.Rev. 2012;6:CD007731.
    3. 91438. Zhao H, Zhang Q, Zhao L, Huang X, Wang J, Kang X. Spore Powder of Ganoderma lucidum Improves Cancer-Related Fatigue in Breast Cancer Patients Undergoing Endocrine Therapy: A Pilot Clinical Trial. Evid Based Complement Alternat Med. 2012;2012:809614.
    4. 108309. Pazzi F, Adsuar JC, Domínguez-Muñoz FJ, García-Gordillo MA, Gusi N, Collado-Mateo D. Ganoderma lucidum effects on mood and health-related quality of life in women with fibromyalgia. Healthcare (Basel) 2020;8(4):520. PubMed

    Valacyclovir

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

  • Headache Additional detail

    Reishi Mushroom

    Recorded for Reishi Mushroom in the same Natural Medicines adverse-effect record shown under Dizziness above.

    Valacyclovir

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

  • Nausea Additional detail

    Reishi Mushroom

    Recorded for Reishi Mushroom in the same Natural Medicines adverse-effect record shown under Itching / A skin rash above.

    Valacyclovir

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

Reported for Reishi Mushroom but not commonly for Valacyclovir: stomach upset, sore throat, a stuffy or runny nose and dry mouth.

Effects for Valacyclovir come from the ADVERSE REACTIONS section of its FDA label; effects for Reishi Mushroom come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Overlapping uses

What Valacyclovir Is Prescribed For, and What Reishi Mushroom Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Valacyclovir is a prescription medicine with approved uses on its FDA label. Reishi Mushroom is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Valacyclovir is prescribed for: Valacyclovir tablets are used in adults to treat cold sores (herpes labialis), genital herpes (initial and recurrent episodes), and shingles (herpes zoster). They can also be taken daily as suppressive therapy to reduce how often genital herpes outbreaks occur, and to lower the risk of passing genital herpes to a partner. In children and adolescents, valacyclovir tablets are used to treat cold sores in those aged 12 and older, and chickenpox in those aged 2 to under 18. Valacyclovir has not been established as safe and effective for most uses in immunocompromised patients, with the exception of suppressive therapy for genital herpes in HIV-infected adults.

Reishi Mushroom has been studied for:

  • Genital herpes studied, not established Reishi Mushroom has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Reishi Mushroom for genital herpes

    Oral reishi mushroom has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Valacyclovir on your own; if you are taking Reishi Mushroom for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Reishi Mushroom or Valacyclovir

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

This page covers Reishi Mushroom only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Valacyclovir page lists 27 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), African Wild Potato (moderate), Banderol (moderate), Biofeedback (moderate) and Caffeic Acid (moderate).

By severity: 1 major · 17 moderate · 9 minor.

From our pharmacist’s overview on the Valacyclovir page

“Valacyclovir (Valtrex) works against herpes outbreaks only if enough of it gets absorbed into your blood, and most of this list threatens exactly that. Of the 27 supplements on file, 17 can change how well oral medicines like this one are absorbed, and the single major-rated entry, activated charcoal, binds drugs in the gut outright.”

Reviewed by 2 · Jul 18, 2026

Open the Valacyclovir interaction page

How much people look this up

Where Reishi Mushroom and Valacyclovir 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 Reishi Mushroom
Top 10%

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

29 days ago today
Medication Valacyclovir
Top 5%

#31 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 Reishi Mushroom reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Reishi Mushroom and Valacyclovir 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 Reishi Mushroom

What is Reishi Mushroom?

Reishi Mushroom
  • Immune support
  • Fatigue and general well-being
  • Stress and sleep
  • Inflammation
  • Heart and cholesterol health

Reishi is a traditional Asian mushroom widely used to support the immune system and overall wellness. Human evidence for most of its claimed benefits is limited or low-quality, so it should not replace proven treatments. It is generally well tolerated for short-term use, but check with your pharmacist or doctor before starting, especially if you are pregnant, nursing, or take other medicines.

Ganoderma lucidum · Ganodermataceae · Fruiting body, mycelium, and spores · Capsules, tablets, powders, extracts, teas, and tinctures

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

Reishi Mushroom: dosing

There is no official standardized dose for reishi. Doses vary a lot depending on whether you use the whole mushroom, a powder, or a concentrated extract.The best approach is to follow the directions on the product label and not exceed them. A pharmacist can help you decide if a product and dose are appropriate for you. If you notice any side effects, stop and check with a healthcare professional.

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

Read the full Reishi Mushroom monograph & all interactions
Medication

About Valacyclovir

What Is Valacyclovir Used For?

Brand name: Valtrex

Valacyclovir tablets are used in adults to treat cold sores (herpes labialis), genital herpes (initial and recurrent episodes), and shingles (herpes zoster). They can also be taken daily as suppressive therapy to reduce how often genital herpes outbreaks occur, and to lower the risk of passing genital herpes to a partner.

In children and adolescents, valacyclovir tablets are used to treat cold sores in those aged 12 and older, and chickenpox in those aged 2 to under 18. Valacyclovir has not been established as safe and effective for most uses in immunocompromised patients, with the exception of suppressive therapy for genital herpes in HIV-infected adults.

Most-Reported Side Effects for Valacyclovir

From FAERS, the FDA’s public side-effect reporting system (70,056 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 4,317 reports
Nausea 3,985 reports
Diarrhea 3,648 reports
Headache 2,964 reports
Fever 2,753 reports
See full Valacyclovir drug information
Keep checking

Other Drugs & Reishi Mushroom

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

0Major
375Moderate
0Minor
2,454No known interaction
375 Moderate 2,454 No interaction
Moderate

375 interactions

Showing 60 of 375 moderate interactions — see all 375 on the Reishi Mushroom page.

No interaction 2,454 drugs checked — show the list

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

Showing the 60 most looked-up of 2,454 medications checked with no known interaction — see the full Reishi Mushroom list.

See the full Reishi Mushroom interactions page
See every supplement checked against Valacyclovir, ranked by severity
Evidence & sources

Reishi Mushroom References

The 17 references that drive our Reishi Mushroom 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. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Tao J, Feng KY. Experimental and clinical studies on inhibitory effect of ganoderma lucidum on platelet aggregation. J Tongji Med Univ 1990;10:240-3. PubMed
  3. Singh AB, Gupta SK, Pereira BM, Prakash D. Sensitization to Ganoderma lucidum in patients with respiratory allergy in India. Clin Exp Allergy 1995;25:440-7.
  4. Lee SY, Rhee HM. Cardiovascular effects of mycelium extract of Ganoderma lucidum: inhibition of sympathetic outflow as a mechanism of its hypotensive action. Chem Pharm Bull (Tokyo) 1990;38:1359-64. PubMed
  5. Kwok Y, Ng KFJ, Li, CCF, et al. A prospective, randomized, double-blind, placebo-controlled study of the platelet and global hemostatic effects of Ganoderma lucidum (Ling-Zhi) in healthy volunteers. Anesth Analg 2005;101:423-6. PubMed
  6. Wanmuang, H., Leopairut, J., Kositchaiwat, C., Wananukul, W., and Bunyaratvej, S. Fatal fulminant hepatitis associated with Ganoderma lucidum (Lingzhi) mushroom powder. J Med Assoc Thai. 2007;90(1):179-181.
  7. Seto, S. W., Lam, T. Y., Tam, H. L., Au, A. L., Chan, S. W., Wu, J. H., Yu, P. H., Leung, G. P., Ngai, S. M., Yeung, J. H., Leung, P. S., Lee, S. M., and Kwan, Y. W. Novel hypoglycemic effects of Ganoderma lucidum water-extract in obese/diabetic (+db/+db
  8. Chu, T. T., Benzie, I. F., Lam, C. W., Fok, B. S., Lee, K. K., and Tomlinson, B. Study of potential cardioprotective effects of Ganoderma lucidum (Lingzhi): results of a controlled human intervention trial. Br.J.Nutr. 2012;107(7):1017-1027.
  9. Jin, X., Ruiz, Beguerie J., Sze, D. M., and Chan, G. C. Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane.Database.Syst.Rev. 2012;6:CD007731.
  10. Kabir, Y., Kimura, S., and Tamura, T. Dietary effect of Ganoderma lucidum mushroom on blood pressure and lipid levels in spontaneously hypertensive rats (SHR). J Nutr Sci Vitaminol.(Tokyo) 1988;34(4):433-438. PubMed
  11. Kanmatsuse, K., Kajiwara, N., Hayashi, K., Shimogaichi, S., Fukinbara, I., Ishikawa, H., and Tamura, T. [Studies on Ganoderma lucidum. I. Efficacy against hypertension and side effects]. Yakugaku Zasshi 1985;105(10):942-947. PubMed
  12. Gao, Y., Lan, J., Dai, X., Ye, J., and Zhou, S. A Phase I/II Study of Ling Zhi Mushroom Ganoderma lucidum(W.Curt: Fr.) Lloyd (Aphyllophoromycetideae) Extract in Patients with Type II Diabetes Mellitus. International Journal of Medicinal Mushrooms 2004;6. DOI
  13. Jin H, Zhang G, Cao X, and et al. Treatment of hypertension by linzhi combined with hypotensor and its effects on arterial, arteriolar and capillary pressure and microcirculation. In: Niimi H, Xiu RJ, Sawada T, and et al. Microcirculatory Approach to Asi
  14. Klupp NL, Chang D, Hawke F, Kiat H, Cao H, Grant SJ, Bensoussan A. Ganoderma lucidum mushroom for the treatment of cardiovascular risk factors. Cochrane Database Syst Rev. 2015 Feb 17;2:CD007259. PubMed
  15. Zhao H, Zhang Q, Zhao L, Huang X, Wang J, Kang X. Spore Powder of Ganoderma lucidum Improves Cancer-Related Fatigue in Breast Cancer Patients Undergoing Endocrine Therapy: A Pilot Clinical Trial. Evid Based Complement Alternat Med. 2012;2012:809614.

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 Reishi Mushroom and Valacyclovir Together: Common Questions

Is it safe to take Reishi Mushroom with Valacyclovir?
We do not list a known interaction between Reishi Mushroom and Valacyclovir. 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 Reishi Mushroom and Valacyclovir have any of the same side effects?
Yes — our sources link each of them separately to 7 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.
Are Reishi Mushroom and Valacyclovir used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Reishi Mushroom in each. That is a conversation for your prescriber, especially if Valacyclovir is being adjusted to a target.
How was the Reishi Mushroom and Valacyclovir combination checked?
Interactions in our licensed database are recorded against drug classes. Valacyclovir is filed under 3 classifications, and Reishi Mushroom has documented interactions with 3 drug classes — none of Valacyclovir'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 Reishi Mushroom interact with any other medications?
Yes. Reishi Mushroom has 375 documented drug interactions in our database — Valacyclovir 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 Valacyclovir interact with any supplements?
Yes. Valacyclovir has documented interactions with 27 supplements in our database — Reishi Mushroom is not one of them. The Valacyclovir 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

Reishi Mushroom monograph Uses, safety profile, and every drug interaction in one place Valacyclovir drug information The full plain-English guide to this medication Valacyclovir supplement interactions Every supplement checked against Valacyclovir, 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 17 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Valacyclovir and Reishi 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.