DNA damages are repaired by many overlapping repair pathways to remove damaged DNA and it also determines cell fate. Nucleotide excision repair pathways repair oxidative base damage and base excision repair pathway removes helical distortions in DNA structure, damages caused by ultra violet radiations and other exogenous oxidative damages. Along with these pathways, DNA Mismatch repair and DNA strand break repair pathways also important in repairing damaged DNA . Endogenus and Exogenus DNA damaging agents: Lipid peroxidation Phospholipid residues of fatty acids are much sensitive to oxidation. Unsaturated fatty acid yields lipid hydroperoxides upon oxidation as its initial products. They may react either with metals or reduced by glutathione peroxidases to produce aldehydes, epoxides etc and unreactive fatty acid alchohals. Malondialdehyde (MDA), croton aldehyde, 4-hydroxynonenal (HNE) and acrolein are major lipid peroxidation aldehyde reactive products which damage DNA by fo...