Poncirus trifoliata Rafinesque has been known to have anti-allergic effects in skin diseases. However, anti-atopic dermatitis effects of P. trifoliata Rafinesque have not been studied yet in skin diseases. The present study evaluated the anti-atopic dermatitis effects of P. trifoliata Rafinesque (PTR) using external treatments on AD. Methods: AD lesions were induced by the repeated application of 2, 4-Dinitrochlorobenzene (DNCB) on the shaved back of BALB/c mice. 100 ㎕ of PTR extracts was applied to the AD lesions for 11 days. Histological assessments, mast cells count and serum levels of IgE were analyzed. The anti-pruritic effects of PTR were examined by the change of scratching frequency and nerve growth factor (NGF) expression. In addition, the anti-inflammatory effects of PTR were examined by the expressions of Th2/Th1 cytokines and pro-inflammatory in dorsal skin. Results: Histopathological findings showed that topical application of PTR decreased the thickness of dermal and epidermal skin compared with the DNCB group. PTR also notably decreased the mast cells count and serum IgE. The scratching behavior of mice and expression of NGF were significantly reduced. In addition, PTR group significantly suppressed the IL-4, IL-6, IFN-γ and TNF-α cytokines compared to the DNCB group. Conclusions: These results indicated that P. trifoliata Rafinesque possess anti-pruritus and anti-atopic dermatitis properties. Therefore, P. trifoliata Rafinesque might be used for treatment of pruritus and atopic dermatitis.