The increased use of nitrogen fertilizers on crops in recent years has stimulated more careful consideration of the inorganic nitrogen fractions in plants and water. Some plants may accumulate large guantities of nitrate. Acute nitrate poisoning occurs follovving absorption in the blood stream and is marked by methemoglobinaemia and vasodilation. The nitrate tolerance of human and animals depends on several factors such as age, mode of nitrate intake, rate of intake and constituents of the diet. This review is an atlept to summarize the present state of knowledge regarding the problem of nitrate accumulation in plant and drinking water.