Chaga: The Siberian Panacea

Scientific Name:  Inonotus obliquus

Common Names:  Chaga, The Birch Clinker, False Tinder Conk, Kabanoanatake (Japan)

Primary Uses: Anti-inflammatory, Immune Stimulant, Antioxidant, Pain management

For wild mushroomers, winter is a time to consume the stores of dried or frozen edibles laid up during the productive summer and fall mushrooming season.  But while you are consuming the last of your dried Black Trumpets and carefully rationing the meager stores of frozen sautéed Chanterelles, consider that there is one medicinal fungus that is most traditionally collected when the leaves are off the trees and snow covers the forest floor.  I refer to Chaga, Inonotus obliquus, also known in this country as The Birch Clinker, and in Japan as Kabanoanatake.

The name Chaga comes from Siberia where this fungus has been revered for several centuries as a tonic and cure-all for many maladies.  I don’t call Chaga a mushroom (though that descriptor does occasionally escape my lips) because the most visible portion of Chaga, and the part collected and used medicinally, is a sclerotium.  A sclerotium is a concentration or mass of hyphae, which normally do not produce spores.  One can envision a sclerotium as a fungal energy storage organ, much like an onion or potato, storing the products of growth until the conditions are right for production of fruiting bodies or, in the case of plants, a resumption of growth after a dry period or after winter.  There are a number of mushroom species that produce fruiting bodies from underground sclerotia including Morels, Grifola (Polyporus) umbellatus, and certain tropical Oyster mushrooms.   Chaga is somewhat different than most fungi, producing a sclerotium above ground, attached to the side of the host tree, rather than underground.

Description: Chaga belongs to the woody polypore group of fungus.  Its close relatives produce leathery to corky annual polypore fruiting bodies on wood or on the ground arising from wood.  The Chaga sclerotium is collected as an irregularly-shaped black mass erupting from the trunk of a living tree, usually a birch, at the site of a wound or side branch of the tree.  A Chaga growth can occur anywhere on the tree from ground level up, and occasionally are 30 feet or higher.  The Chaga is somewhat rounded at times, but is usually irregularly shaped with an outer surface made up of dense black or dark brown material broken up into an irregular angular crust (see examples).  It looks like something that has been fused by fire and cracked upon cooling, hence the common name “clinker”.   This is not a fungus that makes one look for the saute pan and olive oil!    Under that very hard black surface, the interior is brown to golden brown, mottled, and has the consistency of firm cork.  The whole mass can be more than 12-15 inches across and may protrude out from the trunk for almost as many inches, generally becoming smaller in diameter further from the tree.    At other times the Chaga mass might appear to frame the opening created by a broken branch or line an injury to the bark.  In actuality the expanded Chaga is the result of a sclerotium slowing growing outward from the infected heartwood over several years.  Look for bits of birch bark, and sometimes, outer layers of wood caught up in the expanding Chaga.  The actual fruiting body producing the spores of the fungus is small, inconspicuous and not often seen.

I have seen several Chaga “framing” a woodpecker nest hole.  I assume the crafty bird used the Chaga-softened heartwood as an easily made home.  This same habit has been observed and reported upon in the Western US, where woodpeckers seek out mature Douglas Fir with fruiting bodies of Fomitopsis pinicola (the Red-Banded Polypore) and dig out a nesting cavity in the wood softened by the fungus.

Occurrence and habitat: Chaga is a cold-loving fungus found most commonly in the boreal forests of the circumpolar north.  It grows predominately on species of Birch though it also attacks alder, elm, hornbeam and other hardwoods on occasion.   For medicinal use, only those growing on Birch have been recommended and studied.  It is most commonly found in areas with a high water table and/or high humidity such as bottomlands near bogs or on banks and slopes along lakes, streams or rivers. It occurs frequently, if not commonly, throughout Maine and northern New England and further north throughout much of Canada and Alaska.   It is also common in the Great lakes states.   In Southern New England Chaga can be found only in more mountainous localities with colder climates.  Chaga is slow growing and therefore most easily found on mature trees of Paper, and Yellow Birch.  Chaga also grows on Black or Sweet Birch where it occurs.  It is present throughout the year and is traditionally gathered in the winter, perhaps because it is more visible when leaves are off the trees or the wet bottomlands are frozen solid for walking.  A mature Chaga sclerotium of 6-inch diameter is estimated to be 6-8 years old.  In Siberia the Chaga most highly prized grows on Black Birch.

Ecological information: Chaga is a parasite on the trees upon which it grows.  I have seen it growing on a mature tree for many years and such trees often have significant deformities in the area of infection.  The bark and outer layers of the heartwood become incorporated into outer layer of the growing Chaga leaving a depression and scar on the tree if the sclerotium is removed or dies.   It has been my observation that if the tree dies, the Chaga sclerotium also dies within the same year.  I do not know if this is due to the over competition of other fungi such as Fomes fomentarius and Piptoporus betulinus or if Chaga is unable to continue growth as a pure saprophyte.   At times trees seem to out-compete or “throw off” the infection.  These trees continue to carry the distinctive scar at the site.  On Yellow Birch, in particular, I regularly see trees with several scars where a Chaga had grown in the past.  Such trees often have one or more active Chaga as well.  On other trees, especially Paper or Gray Birch, a Chaga “infection” commonly leads to the death of the tree.  Growth of the Chaga mycelium in the heartwood of the tree results in the weakening of the wood and I frequently come upon recently dead Birch in the forest where the wind has snapped the trunk cleanly off at the site of a Chaga growth/ infection.

Edibility: Chaga is not considered edible in the sense of a morel or Chanterelle.  Its woody consistency makes it too dense; think of eating a wine cork. It is well suited for grinding and making into a tea or tincture.

Toxicity: There is no evidence that Chaga is toxic or that the hot water decoction is not well tolerated.

Medicinal Uses:            Folk or traditional: Chaga has been used primarily in Russia and other Baltic countries for at least 300 years as a general tonic and as a treatment for cancers including breast, pulmonary, skin, rectal, and stomach as well as for other gastric ailments.  Chaga has been recommended and used to address liver or heart disease and worms.   Traditionally, chunks of the sclerotium with the black outer rind removed were boiled for an extended period and the decoction drunk as a tea.  At times this tea was also used for enemas to treat colon cancers and other lower bowl complaints.   The “grounds” remaining after making tea were mashed into a poultice and used to promote skin healing and as an antibacterial (Stamets, 2002). Chaga was also considered an internal cleansing agent and has been used for pain control.  In 1955, following some years of research and testing, Chaga was approved for the treatment of cancers by Medical Academy of Science in Moscow (Hobbs, 1995).    After noticing that the residents of Kamchatka, an area in northern Russia, showed no incidence of stomach cancer, an effort was made to determine the cause.  Scientists concluded that the regular consumption of Chaga tea from an early age was the contributing factor (Chang, 2000).  Chaga has also been used traditionally for general pain relief and to address inflammation.

According to Christopher Hobbs (1995), the Khanty people, native to parts of Western Siberia, continue to use Chaga tea in their traditional way to treat tuberculosis, stomachache, and diseases of the stomach, liver and heart.  It is also used as a general cleansing agent and to treat worms.

One of the common names carried by Inonotus obliquus is False Tinder Conk, alluding to the use of this mushroom for fire starting by traditional peoples here and abroad.  I first learned of this from several “primitive skills practitioners” at the MOFGA Common Ground Country Fair where I was giving out samples of Chaga Chai.  They were as surprised at the use of Chaga as a tea as I was of its use as fire starter.  I can’t help but think that we both harbored judgments about the manner in which the other “wasted” a favorite fungus.

Current uses: A preparation of Chaga was licensed and brought to market in the 1960′s by Russian scientists under the name Befungin and is still available and widely used.  It is recommended for use in Russia as a treatment or adjuvant treatment for several forms of cancer, especially those of the gut, genitals and breast.   As with most immune-modulating mushrooms, the polysaccharide components stimulate the body’s immune system to activate macrophages and T-cells and to stimulate production of interferons, interleukins and tumor necrosis factor.

In Russia it is a common treatment for psoriasis.  Lotions and balms made with Chaga are used in Russia to treat arterial and joint disease and in the healing of wounds (Gorbunove et. al. 2005).  Many preparations and extracts are available currently as dietary supplements to improve the functioning of the immune system, as a protection from infection and as a general tonic.

Areas of research:


  • Studies of cancerous mice and using a water and ethanol-based extract of “a yet-to-be delineated polysaccharide component” of Chaga, taken orally, have shown the extract to have significant anti-tumor effects (Kim, YO et al, 2006).  The basis of the four-fold increase in survival rates was through stimulation of immune components such as B-cells and macrophages in the mice rather than by direct action against the tumors.
  • Betulin and Betulinic acid, which are found in the outer, black “skin” of Chaga sclerotium, have shown promise in the treatment of the skin cancer melanoma in laboratory studies utilizing mice, it also showed anti-cancer activity against a number of other cancer cell lines in culture studies (Eiznhamer, DA & ZO Xu, 2004).  The mechanism shown for impeding cancer growth is the induction of programmed cell death (apoptosis) in tumor cells (Tang, Ying Meei, et al, 2003).
  • A number of distinct bioactive triterpenes have been isolated from Chaga.  Among the most abundant is Inotodiol, which has shown “potent” ant tumor activity (Nakata, Tomoko, et al. 2006), (S Taji, 2008).

Anti-oxidant and Free Radical Scavenging

With the increased interest in the damage caused by free radicals in the body and their implications in both ageing and induction of cancers, the fact that Chaga extracts show marked antioxidant potential has garnered a great deal of attention.

  • The melanin component, which is present in higher concentrations in the dark rind of Chaga, has been shown to have significant anti-oxidative action (Babitskaya, BG, et al, 2002).  This activity assists in protection of the genetic material of the cells from the mutation caused by reactive oxidation.  Another study (Nakata, Tomoko, et al. 2006) sought to differentiate between the anti-oxidant capacity of the black outer rind and the brown interior and noted that while both components showed very high anti-oxidative capacity, the activity from the black rind was due to small phenolic compounds extracted with alcohol while a hot water decoction of the interior flesh had the highest anti-oxidant potential.
  • Cultures of Chaga mycelia grown in the presence of hydrogen peroxide (a cause of oxidative stress in cells) were stimulated to produce higher concentrations of melanin and other antioxidant compounds. (Zheng, Welfia, et at. 2008)
  • A water-soluble extract of Chaga has been shown to have an antioxidant effect in cell culture trials.  Many scientists believe that oxidative nuclear DNA damage over the human life span strongly contributes to age related degeneration and the development of cancers (Park, YK et al, 2004).
  • The triterpene extract as well as a polyphenol extract of Chaga showed anti-oxidant activity and the ability to protect cells from oxidative stress (Yong, Cui, DS Kim, & KC Park, 2005).


  • Ethanol extracts of Chaga have shown marked, dose-dependent ability to inhibit the production of the chemical mediators of inflammation (Kim, HG, et al. 2007).   This leads to a reduction in the inflammatory response of the body.
  • An alcohol extract of Chaga, likely triterpenes, has been shown to have anti-inflammatory and pain relieving properties in animal tests (Park YM, et al. 2005).   This supports the traditional uses of this fungus to address pain and inflammation.


  • In studies using diabetic rats, those fed a diet including 5% Chaga or fermented Chaga powder showed considerable increase in chemical markers indicating reduced blood sugar levels and increased insulin sensitivity. (Cha, Jae-Young et al, 2005)

There is also evidence to support the use of Betulinic acid for its anti microbial properties and Betulinic acid derivatives to treat HIV.  The betulin in Chaga is taken from the Birch host and concentrated up to 30% in the outer skin of the sclerotium(             ).  Many betulinic acid compounds are currently sold as dietary supplements and recommended by herbalist practitioners.

Active Components: Triterpenes (lanostanoid-type and others)

Melanin complex

Heteropolysaccharides including Beta glucans

Protein bound polysaccharide (xylogalactoglucose)

Inositols (vitamin Bs)


Ergosterols (provitamin D) & Other Sterols

Betulin and Betulinic acid (concentrated from Birch bark)

Collection and preservation: Because of the nature of its growth, the sclerotium of the Chaga is quite suitable for collection in the winter.  I find that the process of searching for Chaga keeps me aware of the trunks of trees and I have been amazed at how many woodpecker holes, owls nests and other tree-hollow homes I see during a Chaga hunt.  Chaga is best collected using a hatchet or broad chisel and hammer to pry off the growth.   Care should be taken to remove the sclerotium growth without unnecessary damage to the actively growing tree.  Since Inonotus obliquus is a parasite on the tree, it might be of some benefit to the tree to remove the sclerotium, though this would not end the colonization of the tree by the fungus.  It is important to note that, other than a Chaga sclerotium, I would not look at winter as the time to collect medicinal mushrooms for use.  The best time for collecting other species is when the fruiting bodies are actively growing or approaching maturity.

Preparation and use: Chaga has been prepared and is still available commercially (in the Ukraine and Russia) as a tea, syrup, extract, suppository, tablets, aerosol and injection (Hobbs, 1995).  Several companies are currently marketing liquid extracts and Chaga can be found as one ingredient in many herbal preparations.

The most commonly used preparation for Chaga is as a hot tea (decoction) made from the ground sclerotium.  The tea is a refreshing beverage either hot or cold.  A review of the literature will show some difference in the recommended preparation of a hot water decoction of Chaga.  While many recommend boiling the Chaga to make a tea, others suggest a long (48 hours) steeping period with only warm water.   One study of the anti-tumor activity of Chaga showed that the active anti-cancer components are increased in the tea by boiling the decoction and virtually absent in the non-boiled tea.  For the polysaccharides that stimulate host immune response to become available to us, the use of a hot water extraction is necessary.  Therefore I would not recommend the warm water steeping method.

A tincture or double extraction tincture is most effective in extracting the triterpene components along with the polysaccharides and can concentrate these useful components.  Tinctures can be used daily in water, juice or tea as an immune booster tonic.  The anti-inflammatory benefits are helpful in avoiding respiratory ailments and gastrointestinal-related disorders or other inflammation-related issues.

For more information on Chaga, see Mushrooms for Health; Medidinal Secrets of Northeastern Fungi (LINK)

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