Like many folk remedies of long standing, there is probably a rational core to its use. More than 20 different bioactive compounds have been found in chaga mushrooms, some of them with activity against cancer.
The scientific name for chaga mushroom is Inonotus obliquus, a black-and-brown parasitic fungus, of the Hymenochaetaceae family. It grows as a cork-textured mass on the living trunks of mature birch trees. Other common names are clinker polypore, cinder conk, black mass and birch canker polypore. Unlike many fungi, chaga has almost no smell or taste. In cold parts of the world, especially in regions above the 45th parallel north, chaga is abundant and can be harvested in the wild using a chisel or saw to separate it from the tree. The fungus is then powdered or cut into dice-sized chunks. One can soak it in hot water to easily make a tea. Chaga is popular in the folk medicine of not just Russia, but of North America, Finland, Poland, northeast China and Japan. In Russia, it has allegedly been used as a treatment of cancer since at least the 16th century.
There are currently 135 scientific articles in PubMed on chaga mushroom; 44 of these relate to the treatment of cancer. None of these is a clinical trial. I have repeatedly seen references to a long-ago clinical trial, but have not tracked this down. However, for the sake of completeness, I am including the following statement found at many websites:
“In a 48-patient human clinical trial in Poland in 1957, ten patients treated with chaga showed a reduction of tumor size, a decrease in pain, a decrease in the intensity and the frequency of hemorrhaging, and a recovery accompanied with better sleep, appetite and feelings of improvement. Most of these patients were females treated with chaga for cancer of the genital organs or breast cancer.”
Some of the laboratory work is quite interesting, even provocative. In January 2015, scientists in Yangling, China isolated two lignin-carbohydrate compounds, dubbed IOW-S-1 and IOW-S-2, which have anti-cancer activity. A lignin is a complex chemical compound that is usually derived from the cell wall of plants (including trees). The carbohydrates in question bind to the lignins and make them water soluble. The substances were extracted using a hot-water method. But both water extracts and alcohol extracts have been found to have anti-cancer effects. (I shall say more about the extraction process in a moment.)
In the 2015 experiment, the anti-cancer compounds were extracted from chaga powder three times, with water at 60C, i.e., 140F. Alcohol (ethanol) was subsequently used to further extract some components of the chaga. This is an important lead for anyone thinking of making their own chaga tea, for 140F is hot, but not boiling. It is a good rule when preparing chaga tea to extract the beneficial chemicals without damaging or degrading them (as boiling water might do).
Both IOW-S-1 and IOW-S-2 can induce apoptosis (a form of programmed cell death) in cancer cells. “In addition, both carbohydrate-lignin complexes inhibited the activation of the nuclear transcription factor NF-kB in cancer cells,” the authors wrote (Wang 2015). NF-kB, or nuclear factor kappa B, is a key regulator of inflammation.
In the laboratory, chaga has been found to be effective against melanoma (Youn 2014), cervical (Zhao 2014), colon (Lemieszek 2011), lung and breast cancer (Nagajyothi 2014), sarcoma (Chung 2010), lymphoma and leukemia (Patel 2012). It needs emphasizing that -- despite many anecdotes -- we do not know if the same would be true in the human clinical situation. But, by all accounts, chaga is relatively non-toxic, readily available in northern forests and non-patentable. I believe this accounts for the fact that no one is rushing to test its actual effects in cancer. Clinicaltrials.gov currently lists no clinical trials of Inonotus obliquus.
How to Make Chaga Tea
Chaga is readily available over the Internet, including at Amazon.com. One can buy it in powder form or conveniently in capsules. However, I prefer to buy it in chunks, where I can judge for myself the freshness and quality of the product. The two main sources are from Siberia and Maine. Perhaps because I once lived in the state, I favor the Maine product. Chaga is common above the area of Rangeley, Maine.
One simply takes a chunk of chaga, puts it in a container and pours a cup of hot water over it. You then let it sit for an hour or so. You do not want to use boiling water (212F = 100C). The abovementioned scientific article states that water at 140F to 160F is best. The chaga cube can be re-used twice after the initial extraction. Another scientific article indicates that of various water temperatures, 158F (70C) was optimal for the extraction of antioxidants. I tested this with a kitchen thermometer. This is not boiling but still too hot to comfortably keep your finger in for more than a few seconds.
As to alcohol (ethanol) extraction, this can be done with any good grade of commercial vodka, the stronger the better. Save the chaga chunks that have been subjected to water extraction, chop or grind them up, and put them into a vodka bath. This will get at certain beneficial compounds that cannot be extracted by water. You can then drop the desired amount of tincture into any leftover water extract. This will help keep the water extract from becoming mouldy or contaminated. You can then reheat the mixture when you are ready to use it, as this will evaporate off any unwanted alcohol. The result is an extract of medicinal mushroom more powerful than what you are likely to buy online, at a fraction of the cost.