This study was carried to get detailed information about the analeptic effect of yohimbine on succinylcholine muscle relaxant. Succinylcholine was administered intra- venously at a dose rate of 0.05 mg per kg of body weight and then ten minutes after the succinylcholine injection, yohimbine was administered intravenously at a dose rate of 0.1 mg per kg of body weight. The results obtained were as follows. 1. Induction time of muscle relaxation was fast and favourable as 38 seconds. 2. Mean arousal time and mean walk time were significantly shortened by yohimbine administration in the dogs immobilized with succinylcholine (p＜0.01). 3. Heart rate was slightly increased after succinylcholine administration, and increased significantly after yohimbine administration compared to the control group (p＜0.05). 4. Glucose concentration was slightly increased after succinylcholine administration, and decreased after yohimbine administration compared to the control group.