Methylcytisine (Caulophylline) is a nicotinic alkaloid found in Caulophyllum thalictroides, also known as blue cohosh. Methylcytisine is a second potentially hazardous compound identified from blue cohosh. In cultured rat embryos, N-methylcytisine from blue cohosh caused major malformations. At a concentration of 20 ppm the effects included open anterior neural tube, poor or absent eye development, and twisted tail. Higher concentrations of Methylcytisine inhibited overall growth and morphogenesis, in addition to producing similar malformations. In a separate study, Methylcytisine was also found to stimulate the ganglion cells of the cardiac vagus in frogs, paralyze the ganglia of the cardiac vagus in dogs, and produce hyperglycemia in rabbits. Some of the actions of Methylcytisine are similar to nicotine. N-Methylcytisine in blue cohosh-containing dietary supplements has been measured at concentrations ranging from 5-850 ppm. No research has been conducted on the pharmacokinetics or pharmacodynamics of blue cohosh or its constituents; therefore, the clinical significance of the experiments discussed above remains unknown. However, women anticipating a pregnancy may want to avoid using blue cohosh-containing dietary supplements until the potential in vivo teratogenic effects of this botanical are understood.