The efficacy of a few macrocyclic drugs, viz. 1,4,8,11‐tetraaza‐cyclo‐tetradecane (cyclam); 5,7,7’, 12,14,14'‐hexamethyl‐l, 4,8,11‐tetraaza‐cy'clo‐tetra‐decane (cyclam‐S); 1,4,8,11‐tetrahydroxyethyl‐1,4,8,11 ‐tetraazacyclo‐tetradecane (THEC) and 1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetrade‐cane (TMC) and their linear counterparts, viz. triethylene‐tetramine (TETA) and NN'‐bis‐(2‐aminoethyl)‐l,3‐propane diamine (TET) was examined for prevention of mortality and nickel uptake in the body organs of nickel poisoned mice (at the level of 250 μ mole/kg i.p. of NiCl2i.e. LD90or greater), when administered at various molar ratios of nickel vs. drug.