Lack of carcinogenicity of ferric chloride in F344 rats

The carcinogenicity of ferric chloride, a compound that is used as a food additive, a haemostatic or treatment for hypochromic anaemia, was examined in F344 rats of both sexes. It was dissolved in distilled water at levels of 0, 0.25 or 0.5%, and groups of 50 male and 50 female rats were given one of these solutions ad lib. as their drinking water for up to 2 yr. The mean body weights of the treated rats were lower than control group values for both males and females. A variety of tumours developed in all groups, including the control group, but all these neoplasms were histologically similar to those known to occur spontaneously in this strain of rats, and no statistically significant increase in the incidence of any tumour was found in the treated groups of either sex. Thus it is concluded that under the conditions of this experiment, ferric chloride exerts no carcinogenic potential in F344 rats.