Background and Objectives:The essential oil (EO) from Chamacecyparis obtusa (C. obtusa) has immunological activities with anti-oxidant, anti-inflammatory, and anti-bacterial characteristics. The aim of this study was to investigate the effect of EO from C. obtusa on the house dust mite induced chemical mediator production from bronchial epithelial cells. Materials and Methods:BEAS-2B cells were exposed to Dermatophagoides pteronyssinus (DP) and Dermatophagoides farina (DF) with or without various concentration of EO from C. obtusa. Interleukin-6 (IL-6) and IL-8 were measured to determine the activation of bronchial epithelial cells. Nuclear factor kappa B (NF-κB), activator protein 1 (AP-1), and mitogen-activated protein kinase (MAPK) expression and activity were determined with western blot analysis. Results:DP and DF induced IL-6 and IL-8 production from BEAS-2B cells and these chemical mediator productions were effectively inhibited by 0.02-0.04% of EO. DP and DF enhanced NF-κB and AP-1 transcription factor expression and EO from C. obtusa effectively suppressed the expression and activity of theses transcription factors. Conclusions:EO from C. obtusa suppressed the production of IL-6 and IL-8 with inhibition of the expression and activity of NF-κB and AP-1. EO from C. obtusa is a potential value for the treatment of allergic airway inflammatory diseases.