Abstract: The whole blood sample from suspected bongkrekic acid poisoning patient was collected, and 800 μL of methanol precooled at -20 ℃ was added into 200 μL of sample. After shaking for 5 min, the mixture was centrifuged for 5 min, and the supernatant was analyzed by the optimal instrumental working conditions. The bongkrekic acid was separated on the Infinity Lab Poroshell 120 EC-C₁₈ column (150 mm×3.0 mm, 2.7 μm) by gradient elution using mixed solutions composed of 0.1% (volumn fraction) formic acid solution containing 10 mmol·L^-1 ammonium formate and acetonitrile at various volumn ratios, ionzed by double jet stream electric spray ion source with negative mode, identified by MS1-Allions mode, and quantitatively analyzed by matrix-matched working curve. It was shown that the linear relationship between values of mass concentration and peak area was kept in the range of 45-450 μg·L^-1, with detection limit (3S/N) of 3.2 μg·L^-1. Test for the spiked recovery was made on blank whole blood samples at three concentration levels, giving values of recovery in the range of 82.6%-90.1%, and RSDs (n=6) of the determined values ranged from 4.5% to 5.6%. The proposed method was applied to the analysis of the whole blood sample from a suspected poisoning patient, and the bongkrekic acid was detected with detection amount of 2 225 μg·L^-1.