Metamorphosing tadpoles of Rana hexadactyla were exposed to sublethal concentration  of dye effluent for different periods. The prometamorphic tadpoles registered elevation  in the levels of FAA and depletion of BAA. But the tadpoles in metamorphic climax stage  showed abnormal increase in BAA, while the post metamorphic individuals exhibited  rise in BAA and fall in the FAA content.