Abstract: A rapid and sensitive colorimetric micro method for the determination of antimony in blood and urine was proposed.Only.30 minutes were required to digest more than five samples. 1 ml perchloric acid,3 ml conc.HNO₃ and 3 ml conc.H₂SO₄ are added to the sample (1—4 ml of blood).Digest with additional conc.HNO₃ if charring appears.After the decomposition of the exess of perchloric acid is completed,cool in an ice bath and add slowly 5 ml of aqueous solution of NaCl,then 3 ml of water for washing the flassk.The HSbCl₆ is extracted with 5 ml of amyl acetate.The amyl acetate layer is washed with 5 ml of 6N HCl and the upper layer is separated and shaken with a mixture of 0.5 ml of 0.1% crystal violet and 5 ml of 0.3M HCl for one minute.Take the centrifuged colored amyl acetate layer for color measurement in an electric photometer using green yellow filter (590mμ).If the color is too intense,dilute the colored extract with amyl acetate previonsly shaken with a mixture of 0.3M HCl and 0.1% crystal violet. For micro determination of antimony in urine,using 0.5 ml of perchloric acid,0.5 ml of conc.HNO₃ and 3 ml of conc.H₂SO₄,then proceed as above.