Glycopyrrolate and propantheline, being synthetic quaternary ammonium compounds that cannot cross the blood-brain barrier, will not have the vagal center stimulation. The author administered each small dose of glycopyrrolate and propantenline intravenously to normal human volunteers, and compared its effect on the heart rate. The result were as follows. 1) Glycopyrrolate(0.1mg) produced a slight decrease on the heart rate. 2) Propantheline (0.5mg) produced no detectable change on the heart rate. 3) Glycopyrrolate(0.1mg) 10min. after pretreatment with propantheline(0.5mg) produced a significant increase on the heart rate. 4) Propantheline(0.5mg) 10 minutes after pretreatment with glycopyrrolate(0.1mg) produced more significant increase on the heart rate than glycopyrrolate after propantheline. 5) From the above results, it is suggested that the depressive effect of sympathetic ganglion by propantheline may be less than by glycopyrrolate.