Objective:To discuss potential therapeutic mechanisms of Peitu Qingxin Fang therapy for atopic dermatitis（AD） by detecting the level of n-6 fatty acid before and after treatment.Method: Patients with elevated serum total IgE were selected to the trial.The Peitu Qingxin Fang（daily） was orally used to treat for 12 weeks.The severity of AD was assessed with the SCORAD index（SCORAD）.The serum of samples was collected from patients and 20 healthy people.The serum linoleic acid（LA）

γ-linoleic acid（GLA）

two high-linoleic acid（DGLA）

arachidonic acid（AA） were detected by ELISA.Result:Before treatment

serum level of GLA in AD group was lower than the control group（P<0.01）

there was no significant difference of serum levels of LA

DGLA

AA between AD patient and the control group respectively.The GLA/LA ratio was lower than the control group（P<0.05）

there was a negative correlation between serum level of GLA and the SCORAD index（P<0.05）.After treatment

the SCORAD index declined significantly than that before（P<0.01）.The level of serum GLA

GLA/LA increased than that before（P<0.01）.Conclusion: The level of GLA in AD patients with elevated serum total IgE was association with severity of AD.The could regulate n-6 desaturase

which may be possible mechanism for treating AD.