Administration of Nicotiana glauca to four cows from the 50th to the 75th days of gestation induced congenital deformities in their calves. All four calves had arthrogryposis of forelimbs and one also had spinal curvature and rib cage deformity. The plant material contained 0.113% of the piperidine alkaloid anabasine as authenticated by gas chromatography and by infrared spectroscopy. Because of the presence of anabasine at a high concentration and because of its structural relationship to known teratogens, anabasine may be responsible teratogen.