Contact dermatitis (CD) is a common skin condition characterised by inflammation caused by exposure to allergens. In Malaysia, it accounted for a significant portion of skin diseases, with irritant contact dermatitis being the most prevalent type. Ophiocordyceps sinensis, a medicinal mushroom, has been extensively studied in various disease models and has multiple therapeutic properties in treating hyperlipidemia, arrhythmias and other disorders The objective of this study was to investigate the immunomodulatory effects of O. sinensis cultivar OCS02® on sensitized NCTC 2544 keratinocytes. An in vitro assay was conducted to evaluate the cytotoxicity, expression of cytokines, ROS, and lipid peroxidation in sensitised NCTC 2544 keratinocytes exposed to OCS02® cold water extract (CWE). The results revealed OCS02®CWE were less cytotoxic to keratinocytes than paraphenylenediamine (PPD) with half maximal inhibitory concentration (IC50) 650 μg/mL and 17.7 μg/mL respectively. OCS02® CWE (at 250 μg/mL) significant down-regulated the expression of reactive oxygen species, peroxidation of membrane lipid bilayer, interleukin (IL)-18 and IL-6 cytokines in PPD-sensitised keratinocytes (p<0.05). This study reveals that O. sinensis and its extracts possess anti-inflammatory and cytoprotective properties, suggesting their potential utility in managing inflammatory conditions. Furthermore, the immunomodulatory effects observed in cytokine production indicate their promising role in alleviating diseases characterized by chronic inflammation and immune dysfunction. In conclusion, OCS02® CWE may have immunomodulatory application for the treatment of CD.