Chaga, as all fungus, has many medical properties. Mushrooms, of all kinds,have been used in magic/healing for thousands of years. Chaga is well known in Russia for healing stomach illnesses, such as gastritis,and ulcers. An extract from the fungus is used to treat cancers.
Chaga (Inonotus Obliquus) grows very large on some hardwood trees,besides the smaller Birch. It is edible.