This study was performed to evaluate the effects of doxapram after succinylcholine treatment. Succinylcholine was administered intravenously at a dose rate of 0.07 mg per kg of body weight and then ten minutes after the injection of succinylcholine doxapram was administered intravenously at a dose rate of 2 mg per kg of body weight. The results obtained were as follows : 1. Recovery time in dog given doxapram after succinylcholine treatment was shortened comparing with control group. 2. The changes in respiratory rate revealed a maximal increase immediately after the injection of doxapram. Thereafter respiratory rate gradually decreased, and revealed normal levels 20 minutes after the injection of doxapram. 3. The changes in heart rate revealed a maximal increase immediately after the injection of doxapram. Thereafter heart rate gradually decreased, but remained above the levels of control group. 4. Although arrhysthmias were observed after treatment of succinylcholine, these were disappeared after doxapram treatment. And there was no another change on electrocardiograms.