Objective To screen the potential biomarkers in plasma of rats with acute paraquat (PQ) poisoning using gas chromatography-mass spectrometry (GC-MS) based metabonomics technology,and to provide concrete evidence for early diagnosis.Methods Eight Sprague-Dawley (SD) rats were randomly divided into PQ poisoning group (intragastricly administrated with PQ solution 100 mg/kg) and control group (intragastricly administrated with the same volume of normal saline) according to the random number table,with 4 rats in each group.The general situation of rats was observed at 2,24 and 48 hours after administration.The blood of eye sockets was collected,the endogenous small molecule metabolites in plasma were determined with GC-MS method,and metabolic profile analysis and random forest analysis were performed to filter the potential biomarkers.Results ① The rats in PQ poisoning group gradually appeared lack movement,tachypnea,abdominal seizure and other symptoms of poisoning.In control group,the vital signs were stable.② The metabolites in plasma of rat were analyzed with GC-MS analysis,and the diagrammatic figure was plot as combined with principal component analysis (PCA) and partial least squares-discriminated analysis (PLS-DA) model,which showed that the distribution of plasma metabolism in PQ poisoning group was more diffuse but in the control group was more intensive,indicating that the metabolic patterns in two groups were different.From 2 hours after PQ administration,the metabolic trajectory in PQ poisoning group was significantly deflected compared with that of the control group,which was similar to control group until 48 hours,indicating that the metabolites in plasma of rat showed obvious difference in the early period.Five kinds of potential biomarkers with large weights were selected by random forest method which were serine,L-asparagine,hexadecanoic acid,octadecanoic acid,and arachidonic acid,the retention time was 15.259,24.345,33.334,37.695,and 40.254 minutes,respectively.The levels of serine,L-asparagine,arachidonic acid in PQ poisoning group were significantly higher than those of the control group,peaked at 48,48 and 24 hours,respectively (40.884-5.38 vs.28.85±2.32,6.61±1.31 vs.0.76±0.65,14.21±4.28 vs.4.42±1.19,all P ＜ 0.01),and the levels of hexadecanoic acid and octadecanoic acid were significantly lowered,reached tough at 48 hours (39.09 ± 10.23 vs.83.99 ± 20.49,44.03 ± 3.60 vs.140.76 ± 73.91,P ＜ 0.05 and P ＜ 0.01).The changes in these biomarkers were related to the toxicity of PQ,indicating that PQ could interfere the energy and lipid metabolism in rats.Conclusion Combine with the metabonomics analysis,screened plasma serine,L-asparagine,arachidonic acid content in PQ poisoning rats increased significantly,and hexadecanoic acid and octadecanoic acid content decreased significantly,which can preliminary diagnose acute PQ poisoning with animal general performance.