Three groups of rats, reared for a 91-day period, were fed the following diets: Group I, K-deficient, 1% sulfa-diazine; Group II, K-sufficient, 1% sulfadiazine; Group III, (normal control) dog chow. No significant differences were observed between animals on sulfadiazine-containing diets (I, II) in growth, enamel pigmentation, and rates of eruption and attrition of incisors. In these groups there was, however, a striking deficiency of growth, accompanied by severe symptoms of intoxication, and a marked decline of eruption and attrition rates of incisors, as compared to group III. The known blood changes in vit. K deficiency were definitely observed in group I; but the lack of dental differences between K-deficient (I) and K-sufficient (II) groups indicate that vit. K itself does not influence enamel pigmentation nor eruption and attrition of incisor teeth. Observed differences between animals fed sulfadiazine (I, II) and those sulfadiazine-free (III) signify that sulfadiazine given to prevent vit. K formation in the intestine causes severe intoxication and retardation of growth reflected in lowering of eruption and attrition rates of the incisor teeth.