Birch chaga Inonotus obliquus is used as a component of many medicines. This is due to the versatile therapeutic effect associated with the content of a large number of biologically active substances of inorganic, organometallic and organic nature, a high content of macro- and microelements both in a free state and in the form of chelate complexes. To establish the qualitative and quantitative elemental composition of birch chaga, highly sensitive physicochemical methods of analysis were used, such as atomic emission spectroscopy (AES), inductively coupled plasma mass spectrometry (ICP-MS), and neutron activation analysis (NAA). The scientific novelty of this study lies in the conduct of a complex physicochemical elemental layer-by-layer analysis of chaga, the analogs of which have not been found in the available literature. The analyzed samples of birch chaga layers contain the following elements: K, Na, Mg, Ca, Zn, Mn, Cu, Fe, Mo, Co, Cr, P, Br, Se, V, Al, Ba, Li, Ag, Au, Rb, Cs, As, Sb, B, Sr, Pb, Ni, Ti, Be, Ta, U, Th, Sc; the concentration of elements is highest in the outer layer of the fungus. It is noted that the content of both biogenic elements (K, Co, Mn) and potentially toxic (Ag, Br, Rb) is significantly higher than the corresponding clarkes in bios. Differences in the content of elements correlate with modern biochemical concepts of the composition of chaga, and in most cases also correlate with the values of clarkes in bios. The value of the detected toxicant elements does not exceed the MPC.