SDK (skin decontamination kit) is new skin decontaminant which is developed by ADD (Agency for defence development). In this study, four-week toxicity of SDK was investigated using beagle dogs and Sprague-Dawley rats. The beagle dogs and Sprague-Dawley rats were dressed topically seven days per week for 28 days, with dosage of 0, 0.25, 0.8 and 1 g/kg/day. respectively. Animals treated with SDK did not cause any death and show any clinical signs. They did not show any significant changes of body weight, feed uptake and water consumption. They were not significantly different from the control group in urinalysis, ocular examination and histopathological examination. In hematological and serum biochemical assay, there were no-dose-defendent changes. Therefore, SDK was not indicated to have any toxic effect in the beagle dogs and Sprague-Dawley rats when it was dressed topically below the dosage 1 g/kg/day for four weeks.