A detailed procedure has been established for simultaneous analysis of aconitine, mesaconitine, hypaconitine, and jesaconitine in whole blood using liquid chromatography-tandem mass spectrometry (LC-MS-MS). The method uses a new unique polymer column (Shodex ODP2 HP-4B) for separation, which enabled the injection of relatively crude organic extracts without complicated pretreatments. Quantitation was made by mass chromatography with each product ion referenced against dextromethorphan as internal standard. Aconitine and its three analogues showed good linearity over the range of 1.25-40 ng/ml; the detection limits were 0.3-0.5 ng/ml. Validation data including accuracy, precision, and recovery rates are presented. To further validate the present method, the mixture of aconitine, mesaconitine, and hypaconitine (0.2 mg each) was orally administered to rats, and the concentrations of the three compounds in whole blood specimens were measured 15, 30, and 45 min after dosing; their concentrations in rat whole blood were 0.74-18.3 ng/ml. The present LC-MS-MS method is very effective for simple simultaneous analysis of aconitine and its analogues in forensic and clinical toxicology.