Pregnant Sprague-Dawley rats were treated from day 9 through 12 of gestation with either ethanol (12.5% v/v in physiological saline, 0.015 ml/g, i.p.) and nicotine (16.7 mg/kg, s.c), alone or in combination. Corresponding groups of animals received physiological saline in a similar manner and these served as controls. Embryos were recovered on gestational day 12 and were quantitatively assessed on the basis of 16 recognizable developmental endpoints (morphological scores). The head and the crown-rump lengths of the embryos were also measured. Embryos exposed to nicotine and to ethanol-nicotine were significantly affected in their development whereas those exposed to ethanol alone were spared.