[en] The procedures of removal on internally deposited radionuclides from accidentally contaminated individual are divided for two different category such as 1) Physical procedure, and 2) Chemical procedure. Physical procedures include surgical excision and lung lavage. Both procedures are very effective for decorporation but are slight unsafe in procedure itself. Therefore, it is difficult to judge to apply these procedures under balance of risk and benefit. Chemical procedure include 1) Inhibition of intestinal absorption, such as production of insoluble compounds. 2) Capture of radionuclides in entero-hepatic circulation such as Cs-137 by Prussian Blue, 3) Blocking of deposition to target organs or competitive acceleration of excretion by excess administration of stable isotope or analogous element such as stable iodine for thyroid blocking and 4) Acceleration of excretion by chelating agent such as Pb by EDTA, Hg by BAL, Fe by DFOA. Chelation therapy is major procedure of most practical sense. For the removal of transuranic element, Ca-DTPA and Zn-DTPA (1g/day/person) are the most effective agents in conventional use and new developing agent such as TTHA, Puchel and LICAMS are still not in routine use. The advantage and disadvantage of each agent for decorporation therapy were reviewed. The future research trends expected were discussed related with current difficulties on the application of chelating therapy. (author)