Teratogenicity was evaluated in groups of pregnant Charles River COBS CD rats (25/group) given acetone cyanohydrin via gavage at doses of 0, 1, 3 or 10mg/kg/day on days 6 through 15 of gestation. There was no effect of treatment for all animals as indicated by mortality, antemortem and necropsy observations. A slight reduction in body weight gain was noted for mid- and high- dose animals. Statistically significant differences between high dose group and controls (vehicle, deionized water) were observed for the number of corpora lutea/dam and number of implantations/dam. The viable fetuses/dam, postimplanation losses/dam, mean fetalbody weight and fetal sex distribution in the high dose group and all values for the low- and mid- dose groups were comparable to the controls. The incidence of fetal malformations and developmental variations for all fetuses of treated animals were comparable to the control group fetuses.