Solasodine, a spirosolane structured Solanum alkaloid, was gavaged to hamsters at 1184-1628 mg/kg once on the 7th or 8th day of gestation. About 1/3 of all litters from surviving, pregnant dams had 1 or more deformed offspring. There was 50 abnormals among 727 offspring from 84 dams at sacrifice. Abnormalities included 9 spina bifida, 13 major exencephaly, 25 cranial bleb, 2 harelip and 1 anophthalmic types. There were 5 abnormals among 1948 total offspring from 192 control dams. Malformation incidence in controls was 1/10 that in solasodine-gavaged animals. Solasodine gavage also resulted in a large increase in resorptions. Spina bifidas had a protuberance of the skin and other soft tissue in the dorsal mid-line of the lumbosacral region of the fetus. Exencephalics had a prominent dorsocranial defect that fully exposed the brain. Cranial blebs consisted of a soft protuberance of the skin in the mid-line of the interparietal region. The solasodine analogs tomatidine and diosgenin were not teratogenic at dose levels twice as high as the teratogenic dose of solasodine.