Objective：To compare the effects of three main active components of cortex dictamni namely obacunone，dictamnine， and fraxinellone，in the treatment of atopic dermatitis（AD）and explore their mechanisms. Methods：The AD mouse model was established using 2，4-dinitrofluorobenzene（DNFB），and the effects of ethanol extract of cortex dictamni，obacunone，dictamnine， fraxinellone，and dexamethasone on chronic itch induced by AD in mice were observed. The severity degree of skin lesions in mice was evaluated using a skin lesion scoring system. Hematoxylin-eosin（HE）and toluidine blue staining were used to evaluate epidermal thickness and mast cell count in mice. Enzyme-linked immunosorbent assay（ELISA）was used to detect the levels of interleukin（IL）-4， IL -31，and IL -10 in mouse skin lesions. Western blot was used to detect the protein levels of Janus kinase（JAK1），phosphorylated JAK1（p-JAK1），signal transducer and activator of transcription（STAT）3，p-STAT3，STAT6 and p-STAT6. Results：Chronic itch induced by AD in mice was significantly inhibited by the ethanol extract of cortex dictamni. Compared with the model group，two of the three main active componentsof Cortex dictamni，namely dictamnine and fraxinellone，significantly inhibited the chronic itch induced by AD in mice，improved skin lesion symptoms and inflammatory cell infiltration，downregulated the levels of IL-4 and IL-31， upregulated the levels of IL-10，and inhibited the JAK1-STAT3/STAT6 signaling pathway. However，there was no significant difference between the obacunone group and the model group. Conclusion：Dictamnine and fraxinellone may be the main active components of cortex dictamnitoin exerting anti-dermatitis effect.