Common Names
- Cinder conk
- Birch conk
- Clinker polypore
For Patients & Caregivers
How It Works
Human studies on potential anticancer and immunostimulating effects of chaga mushroom are needed.
Chaga mushroom is found in several areas in the Northern Hemisphere, and has been used in folk medicine for various ailments. Laboratory and animal studies show that compounds in chaga can kill cancer cells selectively and stimulate the immune system. Chaga may also reduce fatigue and inflammation, and increase mental sharpness. However, clinical trials are needed to confirm safety and effectiveness for these uses. In addition, chaga may interact with some drugs and is high in oxalates, which may prevent the absorption of some nutrients and can be toxic in high doses.
Purported Uses
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To prevent and treat cancer
Laboratory and animal studies suggest chaga may inhibit the progression of some cancers. Studies in humans are needed. -
To stimulate the immune system
Laboratory and animal studies suggest chaga can activate some types of immune cells. Studies in humans are needed. -
To reduce inflammation
Laboratory and animal studies suggest anti-inflammatory effects. Clinical trials for this use are needed. -
To protect the liver
Although protective effects have been reported, these benefits have not yet been studied or confirmed.
Do Not Take If
- You are taking blood-thinning medications (eg, warfarin): Laboratory studies suggest that chaga may cause additional effects.
- You are taking diabetic medications: Laboratory studies suggest that chaga may also lower blood sugar, causing additional effects.
- You have kidney disease: Chaga is high in oxalates and may cause kidney problems in some individuals.
Side Effects
Special Point
For Healthcare Professionals
Clinical Summary
Chaga mushroom is found on birch and other trees in cold climates. It has been used as a folk remedy for cancer, digestive system diseases, and various ailments in Russia and other northern European countries. The conk that is used medicinally comprises wood from the substrate tree and mycelium of the invasive fungus (12).
In vitro, chaga has demonstrated antitumor (12) (13), anti-mutagenic (9), antiviral (14), antiplatelet (2), antidiabetic (15), antioxidant (8), and analgesic (3) effects. In vivo studies also demonstrate immunomodulating (16), anti-inflammatory, and pain-relieving properties (3).
In animal studies, chaga displayed anti-allergic (17), cognition-enhancing, and antioxidant activities (18). In murine colitis models, chaga exerted anti-inflammatory effects (19). Oral administration of polysaccharides from chaga increased exercise endurance and biological measures related to fatigue (20). Antidiabetic effects have also been observed (4) (27).
Chaga extracts and constituents have demonstrated inhibitory and proapoptotic effects against colon (5) (21) (22), lung (28), and liver cancer (1) cells. Inotodiol from chaga exerted antitumor effects against cervical cancer cells (23). In some studies, chaga demonstrated selective apoptosis in tumor cells with no effects on healthy cells (1). In animal models, it inhibited melanoma cell growth (7).
To date, no clinical trials have been conducted to assess chaga’s safety and efficacy for disease prevention or for the treatment of cancer, cardiovascular disease, or diabetes. Chaga mushrooms are high in oxalates and excessive intake may have toxic effects (24).
Because natural reserves of this fungus have nearly been exhausted, scientists are seeking to develop cultivated substitutes of wild chaga (4) (25).
Food Sources
Mechanism of Action
Oxalic, gallic, protocatechuic and p-hydroxybenzoic acids have been identified in chaga extracts (12). In vitro, antidiabetic effects are attributed to terpenoids that inhibit alpha-glucosidase (15). Anti-inflammatory and pain-relieving properties may occur via inhibition of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) (3). Immunomodulating effects are attributed to Th1/Th2 cytokine secretion in immune cells and regulation of antigen-specific antibody production (16). Anti-quorum sensing activity in chaga conks suggests broader anti-infection attributes beyond immunomodulatory effects (12).
In animal studies, a methanolic extract of chaga produced beneficial effects on learning and memory via decreased malondialdehyde and nitrite levels, decreased acetylcholinesterase activity, and restored glutathione, superoxide dismutase, and acetylcholine levels (18). Antifatigue effects were attributed to polysaccharides from chaga, which increased endurance and glycogen content of liver and muscle in mice, while decreasing blood lactic acid and serum urea nitrogen levels (20). Anti-inflammatory effects in animal colitis models were related to suppression of tumor necrosis factor (TNF)-alpha, iNOS, and interleukin (IL)-1beta (19).
3beta-hydroxy-lanosta-8, 24-dien-21-al, and inotodiol constituents in chaga produce antimutagenic and antioxidative activities (9). Water-soluble lignin derivatives have also been identified as bioactive constituents with anticancer properties (26). A hot-water extract of chaga exhibited inhibitory and proapoptotic actions against colon cancer cells via upregulation of Bax and caspase-3 and downregulation of Bcl-2 (5). Inhibition of colorectal cancer was exerted by the constituent ergosterol via downregulation of the beta-catenin pathway (21). Inotodiol, a triterpenoid isolated from chaga, inhibited proliferation of cervical cancer cells and induced apoptosis in vitro via increased Bax expression, decreased Bcl-2, cyclin E downregulation, and p27 up-regulation (23). Aqueous extracts of chaga inhibited growth of human hepatoma cells via G0/G1 phase cell-cycle arrest and selective apoptotic induction (1). Other apoptotic characteristics can induce caspase cleavage and nuclear fragmentation (7).
Adverse Reactions
As there have been no clinical trials to assess chaga’s safety, there is a lack of information with respect to potential side effects.
Case report
Oxalate nephropathy: Associated with the ingestion of chaga mushroom powder (4-5 teaspoons daily for 6 months), in a 72-year-old Japanese woman with liver cancer (24).
Herb-Drug Interactions
- Antiplatelet or anticoagulant drugs: Chaga extract inhibited platelet aggregation in a murine model (2). It may also have synergistic effects when used with anticoagulant/antiplatelet drugs, but clinical relevance is not known.
- Hypoglycemic agents: In vitro, chaga had additive effects in lowering blood sugar levels (15). Clinical significance is yet unknown.