The purpose of this study was to observe the additive effect of glycopyrrolate and neostigmine on the heart rate in healthy young volunteer. The authors administered glycopyrrolate and neostigmine intravenously, and compared its effect on the heart rate in both drugs. The results were as follows: 1) A small dose of glycopyrrolate(0.1mg) showed a slight decrease in the heart rate. 2) Neostigmine(0.5mg) showed a significant decrease in the heart rate. 3)glycopyrrolate(0.1mg) 10minutes after glycopyrrolate(0.1mg), showed a marked increase in the heart rate. 4) Neostigmine(0.5mg), 10 min. after glycopyrrolate(0.1mg), showed a significant decrease in the heart rate. 5) glycopyrrolate(0.1mg), 10 min. after neostigmine(0.5mg), showed a decrease in the heart rate. 6) The above results suggest that the site of action of glycopyrrolate is at variance with that of neostigmine.