Nitrates enter human body through drinking water, food and air. Ingested nitrates converted to nitrite by microflora lead to methaemoglobinemia, increased free oxide radicals that predispose cells to irreversible damage and effects like cancer, increased infant mortality, abortions, birth defects, recurrent diarrhoea, recurrent stomatitis, histopathological changes in cardiac muscles, alveoli of lungs and adrenal glands, deterioration of immune system of the body.