The chelating agent DTPA (diethylenetriaminepentaacetic acid) is an effective therapeutic substance for the removal of incorporated plutonium. An attempt to review the present knowledge on the subject of removal of incorporated plutonium by chelating agents is made. The efficacy and limitations of DTPA are briefly outlined. The main emphasis is put on; (1) the factors which influence the effectiveness of Ca-DTPA; (2) the local administration of chelating agents at the site of puncture wound; (3) the use of aerosol Ca-DTPA; (4) the efficiency of treatment by pulmonary lavage in vivo; (5) the toxicity of Ca-DTPA; (6) the relative effectiveness of Ca-DTPA and Zn-DTPA. On the basis of the information revealed, the possibilities for an improvement of chelation therapy of internally deposited plutonium are discussed. This can be achieved by the research into (A) the optimum treatment schedule; (B) the removal of plutonium retained in the intracellular space; (C) the possible use of other agents besides Ca-DTPA; (D) the combination of chelating agents and adjuncts to DTPA for removal of plutonium; (E) the efficacy of delayed and long-term therapy on correspondingly lowered incidence of late radiation damage such as osteogenic tumours and lung cancer.