The aim of presents study revealed the effects of purified Microcystin toxin from anabaena circinalis on the levels of antioxidants and lipid peroxidation markers during chronic duration in common carp, the statistical analysis appeared significant differences between all antioxidants at the P0.05 level and lipid peroxidation markers in intraperitoneal common carp and control.superoxide dismutase SOD activity in blood and liver of control (2.2 and 2.5) U/mg respectively while in its activity in treated blood and liver were (4 , 5.7 , 10.6) U/mg and (8.4 , 16.8 , 19.4) U/mg in three dose (3, 6, 9 ) µg/g respectively whereas catalase activity CAT in blood and liver of control (7.56 , 2664) U/mg respectively while in its activity in treated blood and liver were (28.08, 88.56, 30.48) U/mg and (57.36, 53.04, 47.28) U/mg in three dose (3, 6, 9 ) µg/g While glutathione peroxidase GPx in blood and liver of control (13.27 and 22.72) mol/ml respectively while in its activity in treated blood and liver were (32.5, 38.86, 31.34) mol/ml and (61.12, 64.53, 88.33) mol/ml in three dose (3, 6, 9 ) µg/g respectively Whereas the concentration of glutathione in blood and liver of control (30 , 46.33) µmol/ml respectively while in its activity in treated blood and liver were (51.53 , 53.4 , 38.4) µmol/ml and (53.33 , 43, 36.57) µmol/ml in three dose (3, 6, 9 ) µg/g and malondialdehyd concentration MDA in blood and liver of control (0.78 , 0,903) mol/ml respectively while in its activity in treated blood and liver were (2.76 , 4.61 , 6.66) mol/ml and (2.4 , 8.78 , 10.3) mol/ml in three dose (3, 6, 9 ) µg/g