Abstract: The pharmacokinetics and pharmacodynamics of furosemide were studied. Four healthy male volunteers between ages of 30 to 45 years were selected for the studies. Each subject received 5,10,20 and 40 mg of furosemide by oral adminitration. The urinary excretion data were analyzed by PDP-11 computer with a nonlinear least square model-fitting program designed by the author. Disposition of the drug in man can be described by two compartment open model. The pharmacokinetic parameters were as follows: k_a=2.5115 h^-1, k₁₂=0.6441 h^-1, k₂₁=0.7096 h^-1, k_el=1.6018 h^-1, t=0.2053 h. Total increments of urine volume and urinary Na⁺+K⁺ in 3 h after the drug administrations Were linearly related with the logarithm of corresponding doses. Quantitative relationship of pharmacokinetics and pharmacodynamics of furosemide can be characterized by Hill equation. Another equation relating the drug excretion rates and diuretic actions was inducted and by this equation the clockwise hysteresis of furosemide action can be simulated.