Abstract: This study used HPLC to detect the concentrationof morphine in cardiac blood of rats treated withintramuscular injection Of therapeutic and toxicdose morphine.The results Showed, in the groupwith therapeutic dose morphine, the cardiac bloodconcentration of morphine incraesed significantlywithin 96h after death (p<0.ol),these increase Ofthe cardiac blood morphine correlated well withtime. In the groUP with toxic dose morphine，thecardiac blood concentration of morphine did notchange Obviously within 12h after death. butincreased gradually 24h.48h,96h after death (P<0.01). however, the morphine Changes intensity isnot more significant than the therapeutic dose. Thisstudy proved that the dose Of morphine injectedantemortem affects directly the postmortem Cardiacblood morphine levels. It is analysed for thepossible mechanism of the Change.

Key words: morphine, therapeutic and toxic dose, morphine concentration of Cardiac blood, HPLC