Yohimbine was studied to examine its effectiveness in preventing central nervous system(CNS) depression and bradycardia induced by amitraz (N'‐(2,4‐dimethylphenyl)‐N‐[(2,4‐dimethylphenyl‐imino)‐methyl]‐N‐methyl‐methanimide). In control open‐field activity experiments, the dogs showed high numbers of grid‐line crossings in the first 5 min (exploratory phase), and subsequently low numbers of grid‐line crossings (nonexploratory phase). An iv injection of amitraz (1 mg/kg) abolished both the exploratory and nonexploratory phases and caused bradycardia. Yohimbine alone caused a trend to increase the open‐field activity in the nonexploratory phase. In addition, yohimbine prevented the bradycardia and suppression of open‐field activity induced by amitraz. The results suggest that yohimbine has a potential to be used as an antidote for amitraz overdose.