Chaga

Statema, B. C. P.

Fungus

Chaga

Inonotus obliquus

Known today as: A black, cracked, charcoal-like growth on living birch.
Kind: Fungus, in 2 older authorities
Constituents: betulin, betulinic acid, oxalic acid
Poisoning: Oxalate poisoning
Earliest authority here: The Khanty and the Russians
In other databases: GBIF search · Wikidata search

Revised October 3, 2026: Tradition, lore, modern assessment, and sources extended. Checked against its sources, each read in full, in part, or in its abstract. Version 1, first published September 25, 2026.

Caution. Heavy use can damage the kidneys.

Chaga: what was it used for?

Brewed as a tea in Russian and Siberian folk medicine for stomach complaints and cancer.

Chaga: what does modern science say?

Heavy use has caused kidney damage from its oxalates. Chaga concentrates betulin from the birch, which has anti-tumour activity in the laboratory, and its oxalate content is among the highest of any organism: a Japanese woman who took it daily for months went into kidney failure, and other patients have been reported since.

Pharmacognosy & Toxicology

Constituents

Mechanism

Oxalate nephropathy with chronic use.

Toxic dose

Months or years of daily use in the reported cases.

Syndrome

Oxalate poisoning

Kikuchi, Y., et al. (2014). Clinical Nephrology 81. Abstract read · the text read

The abstract of each source, beneath its citation. For Club members. About the Club or sign in.

Constituent names open the compound’s record at PubChem, and “ChEMBL” beside a name opens its record at ChEMBL, the European Bioinformatics Institute’s database of bioactive molecules. Where a mechanism line was checked against ChEMBL (ChEMBL 37, read 1 October 2026), the check is shown with the measured value and its source paper, or says plainly that nothing has been measured. Doses are as the references give them, for description only; this is not medical advice. Each source carries the result of its check against Crossref, PubMed, or the authority’s page: see Verification.

Chaga: what lore surrounds it?

Its use by poor Russians is mentioned in Solzhenitsyn’s Cancer Ward, as Géry and colleagues note.

Among the Potawatomi it is shkitagen, the fungus that holds an ember without going out, carried as a fire-keeper.

Chaga: what did the older authorities say?

The Khanty and the Russians: The Khanty drank it for gastritis and ulcers, and Russian farmers and workers too poor to buy tea drank it as an infusion; the name is from the Komi word for mushroom.
Soviet medicine: Recognised its decoction in 1955 and entered it in the Soviet Pharmacopoeia as Befunginum.

Sources

Kikuchi, Y., et al. (2014). “Chaga mushroom-induced oxalate nephropathy.” Clinical Nephrology 81. Abstract read · the text read
Géry, A., et al. (2018). Chaga (Inonotus obliquus), a future potential medicinal fungus in oncology? A chemical study and a comparison of the cytotoxicity against human lung adenocarcinoma cells (A549) and human bronchial epithelial cells (BEAS-2B). Integrative Cancer Therapies 17: 832–843. Read in full · the text read
Fordjour, E., et al. (2023). Chaga mushroom: a super-fungus with countless facets and untapped potential. Frontiers in Pharmacology 14: 1273786. Read in full · the text read
Lee, S., et al. (2026). Kidney injury induced by high-dose Chaga mushroom consumption: experimental evidence in a rat model. Journal of Korean Medical Science 41: e37. Read in full · the text read

Verification

Checked

October 1, 2026, and October 3, 2026

Passes

Every sentence read against its sources, in the pass over the remaining 343 entries
Every dated or regulatory claim checked by category across the database
Every source read, in full, in part, or in its abstract, and every sentence checked against what was read (October 3, 2026)

Sources

5 cited: 3 read in full, 2 abstract read. 2 with the abstract on file.

Corrections

None were needed.

What was checked, how, and what was found is set out on the Verification page. A checked source is one whose record was found; it does not make the entry medical advice.

Cite This Entry

Version 1 · first published September 25, 2026 · last revised October 3, 2026

Chicago: “Chaga.” In Materia Medica, edited by B. C. P. Statema. Version 1. The Thinking Press, 2026–. Last modified October 3, 2026. https://thethinkingpress.org/materia-medica/chaga.
MLA: “Chaga.” Materia Medica, edited by B. C. P. Statema, version 1, The Thinking Press, 3 Oct. 2026, thethinkingpress.org/materia-medica/chaga. Accessed 8 Oct. 2026.
APA: Chaga. (2026, October 3). In B. C. P. Statema (Ed.), Materia medica (Version 1). The Thinking Press. Retrieved October 8, 2026, from https://thethinkingpress.org/materia-medica/chaga

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