NL·0193Herbarium of the Nature Library
- Name
- Inonotus obliquus
- Family
- Hymenochaetaceae
- Native to
- Boreal and cool-temperate Northern Hemisphere, mainly on birch: Russia, Scandinavia, Baltic, Korea, Japan, Canada, northern USA
- Habitat
- Boreal forest, Birch woodland
Chaga
Inonotus obliquus
Also calledChaga / Beryozovy grib (Russian) · Pakurikääpä (Finnish) · Kabanoanatake (Japanese) · Schiefer Schillerporling (German) · Cinder conk (English)
What looks like a lump of burnt charcoal on a birch trunk is actually a sterile mass of fungus and wood, the conk. Its golden-orange interior has been brewed as tea across Siberia and northern Europe for centuries.
Inonotus obliquus, commonly called chaga, is a fungus in the family Hymenochaetaceae. It is parasitic on birch and other trees. The sterile conk is irregularly formed and resembles burnt charcoal. It is not the fruiting body of the fungus, but a sclerotium or mass of mycelium, mostly black because of a substantial amount of melanin. It is commonly marketed as a dietary supplement for various health benefits but lacks sufficient scientific evidence for safety or effectiveness, and quality can vary due to inconsistent processing and labeling. Wikipedia
What it can do
- iInfects living birch through wounds and decays its heartwood for decades (white rot)
- iiThe black crust is rich in melanin; the interior concentrates betulin and betulinic acid from birch bark
- iiiFruits only once, as a thin pore layer under the bark after the host tree dies
At the table
Eatensterile conk (ground, as decoction or tea)
Not a food. The conk is simmered as tea. It is extremely high in oxalate, and heavy daily use has caused kidney failure (oxalate nephropathy). Don't confuse it with burnt wood or with black Phellinus brackets. Harvest only from birch.
In the medicine cabinet
| Tradition | Use |
|---|---|
| Russian and Siberian folk medicine (incl. Khanty) | Tea for stomach ailments, tuberculosis and as a general tonic |
| Finnish and Baltic folk use | Wartime coffee substitute and health drink |
| Soviet medicine | Befungin, a chaga extract, was approved in the USSR for gastritis |
Weight of evidence
Traditional. Long historical use; little or no modern clinical evidence.
Active compounds
betulin, betulinic acid, inotodiol, melanin, polysaccharides
Fruiting body & spores
Spores
Spores are produced only by a short-lived pore layer under the bark of dead trees. Spore print white to pale yellowish; spores ellipsoid, smooth, hyaline, about 8–10 × 5–7.5 µm
- Dispersal
- Wind-borne basidiospores, which enter living birch through wounds
Where it lives
Recorded sightings
—
geo-referenced records in GBIF, from museums, herbaria and field observers.
Native range
Boreal and cool-temperate Northern Hemisphere, mainly on birch: Russia, Scandinavia, Baltic, Korea, Japan, Canada, northern USA
Drag the globe to turn it. Dots are where records exist, not a range map; darker means more records.
In the old herbals & bestiaries
No plate in the Source Library names this exact species, so these show its closest relatives as the old naturalists drew them: same genus, or the same kind of plant. Click a plate to read the page it came from, with translation.
In the stacks
Searching the stacks…
Every page naming Inonotus obliquus in the Biodiversity Heritage Library →
Marginalia
Aleksandr Solzhenitsyn's novel 'Cancer Ward' (1966) has a doctor who believes Russian peasants avoid cancer by drinking chaga. The book helped spread chaga's fame worldwide.
Curiosity
The word 'chaga' comes into Russian from Komi (tšak), a Uralic language of the Kama basin, where it simply means mushroom.
Kinship
Fact-checked: 2 corrections made to this sheet. Photographs: iNaturalist contributors under the licences shown. Records: GBIF.org. Historical plates: Source Library (CC BY-SA 4.0; originals public domain). Summary text: Nature Library editors and Wikipedia (CC BY-SA). Medicinal and edibility notes are historical and educational, not advice. iNaturalist taxon 127021.