Chaga was completely unknown in the western world, until Russian author and later Nobel laureate Alexandr Solzhenitsyn introduced it to the world in his novel Cancer Ward, whose protagonist is cured of cancer with the help of Chaga. Cancer Ward is thought to be autobiographical, as Solzhenitsyn suffered from cancer himself.

Besides cancer, in folk medicine Chaga mushroom has been used in the treatment of various stomach problems, tuberculosis, hypertension, viral infections, cardiovascular disease and diabetes. Recently it has attracted attention as a potential therapy for HIV infection.

Based on studies Chaga has anti-cancer, anti-inflammatory, antioxidant, immunostimulating, antihyperglycemic, anti-nociceptive (pain-relieving) and antiulcer properties. In a Japanese study Chaga extract displayed higher antioxidant activity than other tested medicinal mushrooms. It also has activity against blood clots and hyperglycemia (elevated blood sugar).

Chaga mushroom has been shown to have anticancer activity in e.g. hepatoma (liver cancer), gastric cancer, uterine cancer, breast cancer, colon cancer, melanoma, cervical cancer and lung cancer. It appears to downregulate the expression of inducible nitric oxide synthases iNOS and COX-2 by downregulation of the inflammatory mediator NF-kappa-B.