The removal efficiency of Several plant extracts of Nagilla sativa linn, Allium sativum sativum and Allium sativum ophioscordon of free radicals from pure DNA molecule at concentration 5 µgm / ml have been studied when we added 1×10-5 M of H2O2 with plant extracts mixture by measuring absorbency at 260 nanometer . Breaking index for nitrogen base pair was calculated. The plant extracts showed high ability in free radicals scavenge when used in concentrations (0.1, 1, 10, 100) µgm / ml which effect in DNA molecule. Also the DNase activity from different plant extracts was measured in DNase agar. Alcoholic mixture activity of three plants in (1،10،100) µgm/ml concentration was studied by monitoring the protection effect on pBR322 plasmid DNA from Escherichia coli which was protect t pBR322 plasmid he plasmid DNA from breaking by H2O2.