The objectives of this study were to analyse and identify the metabolites of diallyl disulfide (DADS) and diallyl sulfide (DAS) in primary rat hepatocytes prepared by collagenase perfusion. According to the results, allyl mercaptan (AM) and allyl methyl sulfide (AMS) were the metabolites of DADS. The highest amount of AMS (0.93±0.08 μg/ml at 90 min) was much less than that of AM (46.2±6.6 μg/ml at 60 min). Combined with the Purge and Trap using a gas chromatography–mass spectrometry (GC–MS) system, it is very useful to detect the trace amounts of metabolites in primary rat hepatocytes. Results also showed that AMS was a metabolite of DAS. The highest amount of AMS in the extracellular fluid of hepatocytes was 0.63±0.16 μg/ml at 30 min of incubation.