The objective of this project is to characterize dose-response relationships and toxicity of scopolamine hydrobromide administered by oral gavage to rats and mice in 2-year chronic studies. Animals will be treated 5 days per week for 2 years. Extra rats will be added to the study to assess potential neurobehavioral effects at 1, 90, 180, 270, 360, and 720 days. In addition, a simultaneous 2-year diet restriction study in mice with a 65-week interim sacrifice for serum hormone and hematology measurements will be performed. At the end of the study, all core study animals will be given gross and microscopic histopathologic evaluations. A 65-week interim sacrifice, including hematology, histopathology, and plasma scopolamine measurements (mice only), will be performed in the chronic study. The results of these studies will be used by NTP to assess the toxicologic and carcinogenic potential of exposure to scopolamine hydrobromide.