The effects of alcohol in prenatal exposure in CD-1-mice were investigated and an experimental protocol for the fetal alcohol syndrome (FAS) was evaluated. Pregnant mice received 20 percent ethanol (64175) in their drinking water on days 1 to 11, 6 to 11, or 7 to 11 of gestation, or 10 percent ethanol on days 2 to 11 of gestation. Fetuses were removed for examination on day 18. Fluid consumption of ethanol groups was less than that of controls but no difference was found in hematocrits. Ethanol treatment did not affect fetal mortality, weight, or development. The authors conclude that the protocol employed is not suitable for producing an overt FAS. They suggest that researchers interested in using the mouse as an animal model of FAS consider the influence of mouse strain and treatment protocol on test outcome.