This review is intended to assess available literature in order to define the range of nitrate/nitrite effects on animals. Though the literature deals primarily with livestock and experimental animals, much of the contemporary research is concerned with human nitrite intoxication. Thus, the effects on man are discussed where appropriate. Some of the aspects of nitrate/nitrite toxicity that are discussed are: (1) factors affecting accumulation in plants and in water; (2) factors affecting toxicity in animals including humans; and (3) both acute and sublethal toxicity. Toxicity of nitrogen oxides and nitros amines are discussed as well as limits of nitrate/nitrite ingestion for humans in both food and water. This literature review includes a bibliography and a summary and conclusions section. Among the conclusions are: (1) the nitrate content of water is a matter for public concern because of the potential health hazard for infants; (2) human infants are far more susceptible than adults to methemoglobinemia; (3) there is little evidence to indicate that nitrosamines are more than a potential hazard to animal or human health; and (4) nitrate toxicity may occur when animals consume forages that have accumulated nitrates as a result of environmental factors. (MR)