To evaluate the effect of Kam Doo-extract (KDE) on organophosphorous (OP)intoxication in mouse, this research was conducted. KDE prescribed with the equal weights of both Padix Glycyrrizae and Simen Glycine was extracted in water at 100$^{circ}$C for 2hr, and concentrated in a vacuum evaporator. Animmal used in this research was ICR-strained male mice (bodyweight: 20 ~ 25g), and induction material for OP intoxication was DDVP(Dichlovos). Toxicity parameters used to evaluate KDE-preventive effect on DDVP were cholinesterase activity, and protection index of KDE against LDso values of DDVP. As the results, KDE prevented the inhibition of cholinesteranse activity due to DDVP-treatment, and inhanced the protecion index. Consequently our experimental data show the KDE will be useful as an preventive agent in respect that KDE is safe and effective against OP intoxication in mouse.