摘要:Ingestion, absorption, metabolism and excretion of nitrate and nitrite in humans and experimental animals are described on the viewpoint that carcinogenic N-nitroso compounds are formed by the reaction of nitrite with amines or ureides. Although nitrate is an inactive substance on animals and most of that administered is excreted in the urine, nitrite which is derived from nitrate in vivo by microorganisms in the digestive tracts has highly pharmacological and biochemical activities. The latest problems on the possibility of the nitrification in the body and the nitrate balance are also reviewed. It seems that nitrate highly affects the human health because the substance is easily reduced to nitrite in the body.