Abstract: Objective To investigate antagonoistic effect of garlic oil(GO) on toxicity of n-hexane by decreasing the formation of 2,5-hexanedione(2,5-HD) in mice.Methods Adult healthy Kunming mice were treated with n-hexane and GO+n-hexane,respectively.The serum was obtained and extracted with ethyl acetate,and the levels of the serum 2,5-HD were determined with gas chromatography.Results The content of 2,5-HD in serum of the mice detected immediately after a single exposure of n-hexane was 0.14±0.14 μg/ml with the peak values of 24.63±3.52 μg/ml at 10 hr and 0.02±0.04 μg/ml at 20 hr.The serum 2,5-HD decreased by 32.1% (P< 0.01) and 24.4% (P< 0.05) at 6 hr after GO pretreatment and post-treatment.Compared to that of the n-hexane group,the content of serum 2,5-HD in GO pretreated group decreased by 26%-54% within 4 hr-14 hr after the administration of n-hexane,with significant differences at 4,6,8 and 10 hours (P< 0.05 or P< 0.01),but the shape and peak time of the curve were not changed.Conclusion GO can significantly inhibit the metablism of n-hexane with the decrease of serum 2,5-HD and result in the deacrease of the toxicity of n-hexane.