Herb & supplement monograph

Chaga Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Chaga interacts with medications. The heart of this page is the interaction list — every drug Chaga is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Chaga is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Chaga Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Chaga drug interaction appears low for most people, since every listed concern is theoretical rather than proven in humans. None of the interactions are rated major, and all of them come from lab or animal research only, with no reported effects in people.

Interactions deserving the most attention

The combinations worth the most care involve blood thinners, diabetes medications, and immunosuppressants. Lab and animal studies suggest chaga may slow blood clotting, lower blood sugar, and stimulate the immune system, so it could in theory add to bleeding risk, cause low blood sugar, or work against transplant or autoimmune medicines. These are closely monitored, narrow-margin treatments where even a small unexpected shift matters, which is why we flag them despite the limited evidence.

What the rest of the list means

Chaga's long list of interacting medications reflects how many drugs fall into just a few broad categories, not hundreds of separate proven problems. Every interaction here is based on predicted effects from lab or animal research, and none has actually been reported to cause harm in people. That does not rule out an effect, but it does mean the concerns remain theoretical for now.

Check your medications against Chaga

Based on HelloPharmacist’s Chaga interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Chaga

327 medications have a known interaction with Chaga, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Chaga using our pharmacist-reviewed interaction data.

AI summaries are generated from our Chaga interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction 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.
Possible. 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
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Chaga combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Chaga affects

Every type of medication (drug category) Chaga is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 3 drug categories Chaga interacts with

Anticoagulant/antiplatelet DrugsAntidiabetes DrugsImmunosuppressants

Anticoagulant/Antiplatelet Drugs

Theoretically, chaga may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
In vitro and animal research suggests that chaga extract can inhibit platelet aggregation. This effect has not been reported in humans.

Likelihood Possible Evidence D

Antidiabetes Drugs

Theoretically, taking chaga with antidiabetes drugs might increase the risk of hypoglycemia.
Animal research suggests that chaga might decrease blood glucose levels and increase insulin levels. This has not been reported in humans.

Likelihood Possible Evidence D

Immunosuppressants

Theoretically, chaga might interfere with immunosuppressive therapy.
In vitro research suggests that certain constituents of chaga stimulate immune function. This has not been reported in humans.

Likelihood Possible Evidence D

Monograph

Chaga: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Chaga is a fungus that grows mostly on birch trees and is used as a tea or supplement, mainly for immune and antioxidant support. Human evidence for its benefits is very limited, and it may raise some safety concerns such as effects on blood sugar, bleeding, and kidney stones. Talk with your pharmacist or doctor before using it, especially if you have a health condition or take other medicines.

Scientific name: Inonotus obliquus
Family: Hymenochaetaceae
Part used: Sclerotium (the dark, hardened growth on the tree)
Common forms: Tea, powder, capsules, tinctures, liquid extracts

People commonly use it for

Immune support
Antioxidant support
General wellness/tonic
Blood sugar support
Inflammation

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Generally used in foods and teas, but human safety data are limited and a few risks have been reported.

PregnancyInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Chaga is a type of fungus (Inonotus obliquus) that grows mainly on birch trees in cold, northern parts of the world, such as Russia, Northern Europe, Canada, and the northern United States. It looks like a dark, crusty, charcoal-like mass on the side of a tree. The part used is the hardened growth, called the sclerotium.

Chaga has a long history in traditional folk medicine, especially in Russia and other parts of Northern Europe and Asia. It is most often prepared as a tea or simmered to make a dark, earthy drink. Today it is also sold as a powder, capsule, tincture, or liquid extract, and is popular as a "superfood" or wellness supplement.

How it works

Chaga contains many natural compounds, including polysaccharides (such as beta-glucans), triterpenes (like betulinic acid, partly drawn from the birch tree), melanin, and various antioxidants like polyphenols.

Researchers think these compounds may act as antioxidants, meaning they could help reduce damage from unstable molecules called free radicals. The beta-glucans are also studied for possible effects on the immune system, and some compounds have been tested for effects on inflammation and blood sugar.

Keep in mind that most of this information comes from laboratory and animal research. How well these effects carry over to the human body is still uncertain.

Effectiveness

Does Chaga work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 3 uses evaluated

3 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

For Chaga, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 3 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate Cardiovascular disease (CVD)

Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral chaga for CVD, there is insufficient reliable information about the clinical effects of chaga for this condition.

Insufficient Reliable Evidence To Rate Coronavirus disease 2019 (COVID-19)

Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral chaga for COVID-19, there is insufficient reliable information about the clinical effects of chaga for this purpose.

Insufficient Reliable Evidence To Rate Diabetes

Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral chaga for diabetes, there is insufficient reliable information about the clinical effects of chaga for this condition.

Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.

Safety & precautions

Chaga has been consumed as a tea for a long time, but solid human safety data are limited. A few specific concerns have been raised:

Kidney stones: Chaga is high in oxalates, which can contribute to kidney stones and kidney damage. There have been reports of kidney injury linked to heavy Chaga use, so people with kidney disease or a history of kidney stones should be especially cautious.
Blood sugar: Chaga may lower blood sugar, which could be a concern for people with diabetes or low blood sugar.
Bleeding: Chaga may affect blood clotting, so use caution if you have a bleeding disorder or are scheduled for surgery.
Autoimmune conditions: Because Chaga may stimulate the immune system, people with autoimmune diseases should talk to their doctor first.

Pregnancy and breastfeeding: There is not enough reliable safety information, so it is best to avoid Chaga during pregnancy and while breastfeeding.

Because supplements are not tightly regulated, product quality and purity can vary. Choose products from reputable companies, and always check with your pharmacist or doctor before starting Chaga.

Side effects

Chaga is generally well tolerated by many people when used in small amounts, but side effects are possible and not well studied.

Reported or possible effects include:

Digestive upset, such as nausea
Low blood sugar symptoms (shakiness, sweating, dizziness), especially in people who are prone to it
Kidney problems with heavy or long-term use, linked to its high oxalate content

Stop use and seek medical care if you notice signs of an allergic reaction (rash, swelling, trouble breathing) or symptoms of kidney trouble, such as decreased urination, swelling, or pain in your side or back.

Chaga: Reported Adverse Effects

Documented safety reports on Chaga from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

Reports by condition

Kidney failure Renal

Orally, there have been two cases of kidney failure and one case of acute nephropathy related to excessive chaga consumption, which contains high concentrations of oxalate.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

Dosing

There is no standardized or officially established dose for Chaga. The amount in supplements and teas varies widely depending on the product and how it is prepared.

The safest approach is to follow the directions on the product label and not exceed the recommended amount. Because of concerns about kidney stones and oxalates, avoid taking very large amounts or using it for long periods without medical guidance.

If you are considering Chaga, talk with your pharmacist or doctor first, especially if you have a health condition, take other medicines, or are pregnant or breastfeeding.

Pregnancy & Breastfeeding

Chaga & Pregnancy

Insufficient reliable information

Insufficient reliable information available; avoid using.

Chaga & Breastfeeding

Insufficient reliable information

Insufficient reliable information available; avoid using.

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

The 9 references that drive our Chaga 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.

Sun JE, Ao ZH, Lu ZM, et al. Antihyperglycemic and antilipidperoxidative effects of dry matter of culture broth of Inonotus obliquus in submerged culture on normal and alloxan-diabetes mice. J Ethnopharmacol 2008;118(1):7-13. PubMed
Hyun KW, Jeong SC, Lee DH, et al. Isolation and characterization of a novel platelet aggregation inhibitory peptide from the medicinal mushroom, Inonotus obliquus. Peptides 2006;27(6):1173-8. PubMed
Kim YO, Han SB, Lee HW, et al. Immuno-stimulating effect of the endo-polysaccharide produced by submerged culture of Inonotus obliquus. Life Sci 2005;77(19):2438-56. PubMed
Kikuchi Y, Seta K, Ogawa Y, et al. Chaga mushroom-induced oxalate nephropathy. Clin Nephrol 2014;81(6):440-4. PubMed
Lee S, Lee HY, Park Y, et al. Development of end stage renal disease after long-term ingestion of chaga mushroom: case report and review of literature. J Korean Med Sci. 2020;35(19):e122.
Kwon O, Kim Y, Paek JH, et al. Chaga mushroom-induced oxalate nephropathy that clinically manifested as nephrotic syndrome: A case report. Medicine (Baltimore) 2022;101(10):e28997. PubMed
Su L, Xin C, Yang J, et al. A polysaccharide from Inonotus obliquus ameliorates intestinal barrier dysfunction in mice with type 2 diabetes mellitus. Int J Biol Macromol 2022;214:312-323. PubMed
Chen S, Ma Y, Li H, et al. Anti-diabetic e?ects of Inonotus obliquus extract in high fat diet combined streptozotocin-induced type 2 diabetic mice. Nutr Hosp 2022;39(6):1256-1263. PubMed
Ye X, Wu K, Xu L, et al. Methanol extract of Inonotus obliquus improves type 2 diabetes mellitus through modifying intestinal flora. Front Endocrinol (Lausanne) 2023;13:1103972. PubMed

Keep reading

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.

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.

Brand directory

Brands that make products with Chaga

212 brands in our database make a supplement containing Chaga.

Nature's Truth 294 products Nature's Way 3,426 products Naturealm 4 products Natures Craft 146 products New Chapter 565 products New Lung 4 products NFH 131 products Nikken Wellness Kenzen 31 products Nomadic Nutrition 1 product Nootopia 2 products Nootropics Depot 354 products North American Herb & Spice 199 products Number One Nutrition 36 products NutraChamps 75 products Nutriana 20 products NutriCology 678 products Nutricost 706 products NutriRise 37 products Nutrivein 37 products NUU3 13 products Om Mushroom Superfood 73 products Onnit 131 products Oomph Naturals 13 products Ora 71 products

Product directory

Supplement products with Chaga

917 products in our database contain Chaga. Open any to see its full ingredient list and every drug interaction we check.

Pharmacist Counseling Corner

Chaga: Common Questions

What is Chaga used for, and does it work?

People use Chaga for a range of reasons, but according to the Natural Medicines database the current clinical evidence is insufficient to confirm it works for the specific conditions it has been studied for. See the graded list on this page, and talk to your pharmacist or doctor before relying on it for any condition.

Does Chaga interact with prescription medications?

Yes. We list 327 medications with a known interaction with Chaga. Use the checker above to see how Chaga interacts with a specific drug.

How are Chaga interactions rated?

Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.

Is it safe to take Chaga with my medications?

It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.

Where does this Chaga interaction information come from?

Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.

What is Chaga used for?

People most often use Chaga for immune and antioxidant support and as a general wellness tonic, usually as a tea or supplement. However, strong human evidence that it treats or prevents any disease is lacking.

Is Chaga safe to take every day?

Chaga has been used as a tea for a long time, but daily long-term use has not been well studied. Because Chaga is high in oxalates and has been linked to kidney problems in some reports, it is best to use it cautiously and check with your pharmacist or doctor.

Can I take Chaga while pregnant or breastfeeding?

There is not enough reliable safety information, so it is best to avoid Chaga during pregnancy and while breastfeeding.

Are there people who should not use Chaga?

People with kidney disease or a history of kidney stones, diabetes or low blood sugar, bleeding disorders, autoimmune conditions, or upcoming surgery should be cautious and speak with a healthcare provider first.

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

Keep exploring

Products that contain Chaga

A rotating sample of real supplements in our database that list Chaga — open any to see its full ingredients and every drug interaction we check.

See all 917 products with Chaga →

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Chaga Drug Interactions, Uses, Effectiveness, Safety & More

Your Choice:

Chaga Drug Interactions: The Bottom Line

Drugs that interact with Chaga

Don’t want to scroll the list? Just ask.

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Likelihood — How Well It’s Documented

Where This Data Comes From

The kinds of drugs Chaga affects

Chaga: Uses, Safety & Side Effects

Overview

How it works

Does Chaga work?

Safety & precautions

Side effects

Chaga: Reported Adverse Effects

Dosing

Chaga & Pregnancy

Chaga & Breastfeeding

References & further reading

Brands that make products with Chaga

Supplement products with Chaga

Chaga: Common Questions

Related supplements & herbs

Products that contain Chaga

Have a question about Chaga?