The pharmacological actions to methanol extract(PME) obtained from Plantaginis semen were examined in the rabbit. 1) PME, when administered into the vein of rabbit, produced the fall of blood pressure and stimulation of respiration. The former action was inhibited by atropine but the latter not affected by atropine. 2) PME caused contraction in both isolated intestinal and uterus strips, atropine blocked the contraction of intestinal strips while did not the uterus contraction. 3) PME decreased the heart rate of rabbit anesthetized with urethane. 4) PME elicited antidiuresis with doses ranging from 10mg/kg. The antidiuresis appeared to be related to the hemodynamic changes decreases in the renal plasma flow and glomerular filtration rate. Urinary sodium and potassium decrease in the renal plasma flow and glomerular filtration rate. Urinary sodium and potassium decrease in relation to the diminished filtration.