The free radicals are reactive molecules with electron-rich groups produced during metabolic reactions occurring in the cells. These free radicals are collectively known as reactive oxygen species (ROS) and reactive nitrogen species (RNS). Lipid peroxidation products and protein carbonyls species are under the group of ROS, and nitric oxide and peroxynitrites are under the group of RNS. The malondialdehyde that reacts with LDL-C indirectly induced the risk of atherosclerosis. The protein carbonyls acts as marker of protein oxidation and exerts damage to proteins. The nitric oxide plays an important role in DNA damage, inflammation, proliferation of cancer cells, and dysfunction of apoptosis. The peroxynitrites could induce the process of lipid peroxidation, DNA damage, and may exert chronic damage to all biomolecules. The aim of the present study is that the free radicals may react with biomolecules of the cells and play an important role in the development of chronic disease conditions in the humans.