Chaga
Inonotus obliquus · Chaga Mushroom · Clinker Polypore
Snapshot
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Chaga (Inonotus obliquus) is a fungus that grows on birch trees in cold climates and is used in northern European folk medicine, usually as a bitter tea or as capsules, tablets, and powders1. Supplementation is driven by its proposed immune-modulating and anti-inflammatory activity via cytokine signaling, with uses that follow in immune function, inflammation, and liver protection1. The typical patient is an adult seeking general immune or anti-inflammatory support.
No published human trial has tested chaga for a clinical outcome; the research rests on animal and cell studies. In rats, a 2026 study found that high-dose chaga powder produced oxalate crystal deposition and tubular kidney injury, and no human trial has tested this. Over two thousand products listing chaga are marketed, mostly as capsules and powders; see Form comparison.
The most consequential caution is renal: the Memorial Sloan Kettering monograph reports oxalate nephropathy and end stage renal disease in case reports after prolonged chaga powder intake, some without renal recovery1. For patients on warfarin, the same monograph asks them to talk with their healthcare provider because chaga may increase bleeding risk1.
Last updated October 16, 2026. Read how we make monographs.
In the full monograph
17 sources, 11 studies
- When to useThe situations practitioners use it for, each with the reason and the study behind it.
- SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
- InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
- Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
- How it worksWhat it is and how it works in the body, in plain terms.
- Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
- Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
- Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.
Sources
- 1MSKCCmskcc.orgMemorial Sloan Kettering — About Herbs, Botanicals & Other Products
- 2US product labelsdsld.od.nih.govWarnings printed on US dietary supplement labels with this ingredient, from the NIH Office of Dietary Supplements' Dietary Supplement Label Database (DSLD). Manufacturers' precautions, not evidence of harm