The purpose of this study was to clarify the effect of ethanol on rat molar tooth development. Pregnant rats were fed 25%-ethanol solutions or ethanol-free water up to delivery, and tooth germs, as well as fully developed teeth, obtained from the offspring (ethanol-exposed rats or control rats) were subjected to morphometric analysis and immunohistochemistry. No significant differences were observed in terms of tooth size between the ethanol-exposed and control rats. Moreover, no abnormalities in cusp number, form or dental surface structure was noted in the ethanol-exposed rats. In the ethanol-exposed rats, the tooth development showed a slight retardation in comparison to the controls. Morphological alteration in tooth germs was not observed in the experimental rats. Both bone morphogenetic protein-4 and basic fibroblast growth factor-2 were immunolocalized in the cells composing the tooth germs in the ethanol-exposed rats. No differences, however, were found in immunostaining intensity between the ethanol-exposed and control rats. Taken together, the results indicate that the effect of ethanol on tooth development was weaker than expected in the rat FAS model. which looked at anthropometric measurements and oral health status in FAS children found no significant difference in prevalence of enamel opacities between FAS patients and controls 5). Thus, although there seems to be some relationship between intake of alcohol during pregnancy and abnormal tooth development in children, the precise nature of this relationship remains to be clarified. Tooth development results from a process of mutual cellular proliferation and differentiation in epithelial and mesenchymal cells in the tooth germ during the fetal stage 8,9). A variety of growth factors act as inductive signals in embryonic tissue interaction 8-10). Among them, bone morphogenetic proteins (BMPs) 11-14) , fibroblast growth factors (FGFs) 15-17) and epidermal growth factor (EGF) 18,19) are believed to play a particularly important role in the process of tooth development. Therefore, in order to obtain a better understanding of how alcohol intake affects tooth development, it is necessary to study the effect