This book is prepared to give information on the chemistry and toxicity of nitrites. Several factors can affect a person’s health like exposure to certain environmental chemicals, particularly to NO3− and NO2−. Several factors including drugs and certain chemical exposures can all be listed as risk factors in high exposure to NO3−/NO2−. Besides, in rural areas, drinking well water is the primary source of NO2− exposure.It is extremely difficult to avoid exposure to NO3− and NO2−. However, several measures have to be taken to prevent high exposure, especially for susceptible populations like children. Parents can reduce the intake of NO3− and NO2− in their children’s diet by reducing the amount of preserved meats they eat (such as sausage, bacon, hot dogs). Besides, it should not be forgotten that vegetables contain high amounts of NO3− and NO2−, and therefore should be given with attention in the first years of life.