PURPOSE: Due to its efficacy in caries prophylaxis and easy application, sodium fluoride (NaF) is still used for caries prevention in the form of fluoridated drinking water, fluoride tablets, fluoridated salt or milk. Effect of fluorides on various metabolic levels in hard and soft tissues, namely respiration as well as carbohydrate, protein, enzymatic and vascular metabolism, can disturb detoxication of fluorine compounds administered orally. The study objective was morphological examination of the liver of young and mature rats exposed to NaF in drinking water from conception till maturity, as well as after its withdrawal. MATERIAL AND METHODS: In the initial stage of the experiment, 30 female Wistar rats, 180-200 g body weight, were divided into 3 groups: one control and two experimental groups (I, II). Female rats in the experimental groups received fluorine in aqueous solutions of sodium fluoride (NaF) at a concentration of 10.6 mg NaF/dm3 (group I) and 32.0 mg NaF/dm3 (group II). RESULTS: The pathomorphological changes observed in the liver, particularly of young rats exposed,to fluorides at superoptimal doses can help determine to what degree oral fluoride caries prevention is safe and whether it should be implemented. The transitory nature of pathomorphological changes in hepatocytes indicates adaptive potentials or defence mechanisms against orally administered sodium fluoride.