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Chaga - Inonotus obliquus

We’re back with another heavy hitter which will continue the trend since we’ve moved to substack. This weekend, I went up to Maine (again) and found one of the more prominent members of the medicinal mushroom and wellness worlds. You may have read about it, or even consumed it in a tea or supplement, but we’re talking about Chaga (Inonotus obliquus). Let’s learn a little about this funky chunk of fungus and see what these potential medicinal benefits are all about.

Inonotus obliquus

Fun Ecological Facts

Right off the bat, the black, gnarled crust you see above isn’t actually a mushroom. It is a tight bundle of hyphae (filamentous strands, the body of the fungus) called a sclerotium. This sclerotium (pl. sclerotia) serves as a form of nutrient storage for the fungus. Wield this information in the form of a pompous “well actually…” the next time you hear some poor soul refer to chaga as a mushroom.

This fungus is considered rather uncommon, but I find it quite routinely up in Maine and New Hampshire. I have noticed I don’t see it in birch forests at more southerly latitudes (the Catskills) nearly as often. Though I haven’t seen it anywhere else, the fungus is found throughout northeastern North America and across temperate forests of the northern hemisphere (but not on the west coast).

Inonotus obliquus

The actual fruiting body of the fungus is hard to find. The fungus exists initially as a parasite on a handful of different tree species, but is almost always found on birch - specifically paper birch (Betula papyrifera) and yellow birch (Betula alleghaniensis). The tree can live anywhere from ten to eighty years with the fungus leaching nutrients.¹ Birch trees are already short-lived trees, so perhaps the fungus doesn’t cause much detriment at all. I may be biased toward the fungus, but there are some parasites that are like that.

When the tree eventually dies, the fungus then becomes a saprobe and assists in digesting the wood. Additionally, upon the death of the tree, the fungus then produces the “mushroom” aka the fruiting body. This timing suggests the fungus depends on the tree and is sending out spores to find a new, living host. Here is what the fresh fruiting body (a polypore growing resupinate) looks like:

Inonotus obliquus
The elongated pores look like icicles or stalactites. It always grows underneath the bark of the recently dead tree. Image courtesy of Josh Fecteau of Kennebunkport, ME and

I found what may have been parts of the old fruiting body. You kind of have to use your imagination, and it should be noted the mushroom is known to get devoured by insects quickly after formation, but these growths on the back of the tree (underneath the bark) could be remains of a desiccated fruiting body:

Inonotus obliquus

Medicinal Properties

You can find a load of information on the medicinal properties, but if you’re a stickler (like Michael Kuo who went out of his way to poo-poo the idea) than you’ll probably not have any of this. Conversely, chaga has been used for at least a millennium in Russian folk medicine and before that by the Khanty, indigenous peoples of the Ural Mountains. I’m going to touch on just a few medicinal aspects as it would be easier to list the ailments and illnesses that chaga doesn’t allegedly address than it would be to summarize all the purported benefits.

Inonotus obliquus

Clinical trials in humans are limited - in that I could only find one and it was from a company that sells a copyright protected chaga supplement. There is, however, a study in mice that showed an aqueous extract could suppress cancer growth and modulate overall health.² The fungus turns betulin from birch trees into betulinic acid which might be the specific compound through which the chaga conveys these anti-cancer properties.³

Further studies suggest the crusty conk also has anti-inflammatory and antioxidant properties.⁴ The antioxidants come from the abundance of melanin which gives chaga that dark, charred appearance. Some claim it is the most antioxidant abundant food in the world (which seems to be substantiated online, but I couldn't find a definitive source) and it does indeed have ten times as many antioxidants as elderberries (we're comparing ORAC or Oxygen Radical Absorbance Capacity scores here, folks).⁵

Inonotus obliquus
I always look for those yellow spots in chaga - I think they’re visible strands of mycelium but I’m not really sure. Larger specimens (some growing to the size of bowling balls) can be entirely yellow on the inside which is why chaga also has the nickname “Black Gold”.

I’m a believer, so I’ll usually harvest a little chunk (like above), crumble it up, drop it in water, and let the brew simmer on low (not boiling, which may deteriorate some of the beneficial compounds). It makes a dark, earthy tea (aka an aqueous extract) that you can mix with maple syrup for a really tasty beverage if at nothing else. I’ve also used the ground up sclerotium to make tinctures with Catskill Fungi. There are some internet rumblings that chaga from dead trees isn’t beneficial, but personally I don’t follow those rumbles.

Another double digit references week. I gotta start mailing it in and get back below five.

Looking forward to it,



1) Kuo, M. (2020, July). Inonotus obliquus. Retrieved from the MushroomExpert.Com Web site:

In-text Citations

1) Robert Dale Rogers. Medicinal Mushrooms: The Human Clinical Trials. Prairie Deva Press, 2020, p. 56.

2) Arata S, Watanabe J, Maeda M, Yamamoto M, Matsuhashi H, Mochizuki M, Kagami N, Honda K, Inagaki M. Continuous intake of the Chaga mushroom (Inonotus obliquus) aqueous extract suppresses cancer progression and maintains body temperature in mice. Heliyon. 2016 May 12;2(5):e00111. doi: 10.1016/j.heliyon.2016.e00111. PMID: 27441282; PMCID: PMC4946216. 3) Szychowski KA, Skóra B, Pomianek T, Gmiński J. Inonotus obliquus - from folk medicine to clinical use. J Tradit Complement Med. 2020 Aug 22;11(4):293-302. doi: 10.1016/j.jtcme.2020.08.003. PMID: 34195023; PMCID: PMC8240111.

4) Géry A, Dubreule C, André V, Rioult JP, Bouchart V, Heutte N, Eldin de Pécoulas P, Krivomaz T, Garon D. 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). Integr Cancer Ther. 2018 Sep;17(3):832-843. doi: 10.1177/1534735418757912. Epub 2018 Feb 27. PMID: 29484963; PMCID: PMC6142110.


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