The chelating drugs namely ethylenediamine tetraacetic acid (EDTA), 1,2,cyclohexylenediamine tetraacetic acid (CDTA), hydroxyethylenediamine triacetic acid (HEDTA) diethylenetriamine pentaacetic acid (DTPA), and triethylenetetraamine hexaacetic acid (TTHA), were examined for the mobilization of nickel from body organs of sham operated and partially hepatectomized rats in early nickel poisoning. These chelating drugs successfully reduced the body burden of nickel from both the nickel treated experimental groups. EDTA was relatively more effective in reducing the hepatic content of nickel while CDTA and HEDTA were more effective in reducing its renal content. These drugs also reduced nickel burden in heart and lung to variable degrees. The over all efficacy of the chelating drugs are in the order:. EDTA > CDTA > HEDTA > TTHA > DTPA. © 1986.