Areversed phase liquid chromatographic method for determination of acetaminophen in human plasm andthe pharmacokinetics ofacetaminophen in humans were studied . The drug was extracted from human plasm with diethylether . A C1 8 column (5 μm ,200 m m ×4 .6 m m ) accompaned with the mobil phase composed of methanol 0 .022 mol L Na Ac 0 .126 mol L H Ac (25 ∶50 ∶50) was used . Salicylic acid was used as internal standard and detectivewavelength was 233 nm . The calibration curves showed good linearity overthe range of 0 .112 μgml. The recoveries ofacetaminophen were 94 .3 % 101 .7 % for plasma . After a single dose of 500 mg of acetaminophen granula , theconcentration time curves conformed to one compartment model. Cm a x = (5 .94 ±0 .69) μgml , tm ax = (0 .73 ±0 .32)h ,t1 2 Ke = (2 .38 ±0 .85) h , t12 Ka = (0 .21 ±0 .14 ) h , A U C0 → ∞ = (25 .87 ±6 .73) μg·h ml . Areversed phase liquid chromatographic method for determination of acetaminophen in human plasm and the pharmacokinetics of acetabamin in humans were studied. The drug was extracted from human plasm with diethylether. A C1 8 column (5 μm, 200 mm × 4 .6 mm) accompaned with the mobil phase composed of methanol 0. 022 mol  L Na Ac 0.126 mol  LH Ac (25:50:50) was used. Salicylic acid was used as internal standard and detective wavelength was 233 nm. The calibration curves showed good linearity overthe range of 0. 1 12 μg ml. The recoveries ofacetaminophen were 94 .3% 101 .7% for plasma. After a single dose of 500 mg of acetaminophen granula, theconcentration time curves conformed to one compartment model. Cm ax = (5.94 ± 0.69) μgml, tm ax = (0.73 ± 0.32) h, t1 2 Ke = (2.38 ± 0.85) h, t12 Ka = (0.21 ± 0 .14) h, AU C0 → ∞ = (25 .87 ± 6 .73) μg · h ml.