The present invention discloses a method for the production of low ash activated charcoal from a carbon-containing raw material such as peat, in which method a damp mass of raw material is subjected to a hydrothermal carbonization process, in which the mass is heated to a temperature of 150 to 350 C and the process pressure increased to 10 to 40 bar, and the carbonized material obtained from the hydrothermal carbonization process is activated by heating it to a temperature above 400° C. The present invention further relates to the use of carbonized material obtained from the hydrothermal carbonization process for the production of activated charcoal.