In this study, LCZ significantly inhibited ear swelling associated with TPA‐induced irritant dermatitis in mice at concentrations of more than 1%, and LCZ dose‐dependently and remarkably suppressed the increases in the MPO activity, KC content and MIP‐2 content in TPA‐induced irritant dermatitis. The gene discussed is CXCL2; the disease is irritant dermatitis.