Drug & supplement interaction

Reishi Mushroom + Tolbutamide

Tolbutamide brand name: Orinase.

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

Reishi Mushroom has a moderate interaction with Tolbutamide. Theoretically, reishi mushroom might have additive effects with antidiabetes drugs.

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

Reishi Mushroom and Tolbutamide

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

Moderate

ANTIDIABETES DRUGS

Why this applies to Tolbutamide

Tolbutamide falls under ANTIDIABETES DRUGS — the group Reishi Mushroom interacts with.

Theoretically, reishi mushroom might have additive effects with antidiabetes drugs.
Animal research suggests that reishi mushroom decreases blood sugar. However, in patients with type 2 diabetes, taking reishi mushroom does not reduce fasting glucose levels, and its effects on glycated hemoglobin are inconsistent.
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 with reishi and tolbutamide (Orinase). The concern is simply additive: reishi might nudge your blood sugar a little lower on its own, and tolbutamide already does that job by prompting your pancreas to release insulin. Stack the two and, in theory, your sugar could dip more than expected.

Now, the honest part: this idea mostly comes from animal and lab work. In actual people with type 2 diabetes, reishi hasn't reliably lowered fasting glucose, so the real-world effect looks weak. Still, it's worth watching for signs of low blood sugar (shakiness, sweating, dizziness, confusion). Don't change anything on your own. Just check your readings and run reishi past your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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
  2. 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
  3. 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

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

Reishi Mushroom Also Interacts With Other Medications

Reishi Mushroom has 374 moderate known drug interactions in our database — the Tolbutamide one above is one of them. If you take anything else, check it against the full list below.

Moderate 374 No known interaction 2,456 (incl. Tolbutamide)
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.

Everything else you take

See Every Supplement That Interacts With Tolbutamide

This page covers Reishi Mushroom only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tolbutamide page lists 305 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Siberian Cocklebur (major), Acai (moderate), Adrafinil (moderate) and African Wild Potato (moderate).

By severity: 2 major · 255 moderate · 48 minor.

From our pharmacist’s overview on the Tolbutamide page

“People take tolbutamide (Orinase) to lower blood sugar in type 2 diabetes, and diabetes is exactly the condition supplement shelves target, which is why this list runs to 305 ingredients and deserves real caution. Of those, 239 also push glucose around, most often downward, so combining them can drive sugar lower than intended.”

Reviewed by 2 · Jul 18, 2026

Open the Tolbutamide interaction page

How much people look this up

Where Reishi Mushroom and Tolbutamide 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 5%

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

29 days ago today
Medication Tolbutamide
Steady interest

#1,734 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 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.

Read the full Reishi Mushroom monograph & all interactions
Medication

About Tolbutamide

What Is Tolbutamide Used For?

Brand name: Orinase

  • Tolbutamide is used along with diet and exercise, and sometimes with other medications, to treat type 2 diabetes (condition in which the body does not use insulin normally and, therefore, cannot control the amount of sugar in the blood). Tolbutamide is in a class of medications called sulfonylureas. Tolbutamide lowers blood sugar by causing the pancreas to produce insulin (a natural substance that is needed to break down sugar in the body) and helping the body use insulin efficiently. This medication will only help lower blood sugar in people whose bodies produce insulin naturally. Tolbutamide is not used to treat type 1 diabetes (condition in which the body does not produce insulin and, therefore, cannot control the amount of sugar in the blood) or diabetic ketoacidosis (a serious condition that may occur if high blood sugar is not treated).

  • Over time, people who have diabetes and high blood sugar can develop serious or life-threatening complications, including heart disease, stroke, kidney problems, nerve damage, and eye problems. Taking medication(s), making lifestyle changes (e.g., diet, exercise, quitting smoking), and regularly checking your blood sugar may help to manage your diabetes and improve your health. This therapy may also decrease your chances of having a heart attack, stroke, or other diabetes-related complications such as kidney failure, nerve damage (numb, cold legs or feet; decreased sexual ability in men and women), eye problems, including changes or loss of vision, or gum disease. Your doctor and other healthcare providers will talk to you about the best way to manage your diabetes.

See full Tolbutamide 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
374Moderate
0Minor
2,455No known interaction
374 Moderate 2,455 No interaction
Moderate

374 interactions

Showing 60 of 374 moderate interactions — see all 374 on the Reishi Mushroom page.

No interaction 2,455 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 2,455 medications checked with no known interaction — see the full Reishi Mushroom list.

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

Can you take Reishi Mushroom with Tolbutamide?
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 Reishi Mushroom and Tolbutamide 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 Tolbutamide 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.