Atopic dermatitis (AD) can occur in both children and adults, and the symptoms include itching and eczema, which in turn cause patients to suffer. Ophiopogonin D (OP-D) is a steroidal glycoside from Radix Ophiopogon japonicus, which is well known as an effective anti-inflammatory herbal medicine in many Asian countries. In this study, we aimed to investigate the anti-inflammatory effects of OP-D, using an AD mouse model and inflamed HaCaT cells. Through a histopathological analysis, we were able to confirm the suppressive effects of OP-D on skin thickening and the mast cell activation in AD-like mouse back skin tissues stimulated by DNCB. In addition, we detected significant decreases in cytokine expression levels through multiplex assessment assays of the OP-D-treated mice blood. We observed the anti-inflammatory effect of OP-D in the spleen, causing weight loss in the spleen and in the mRNA expression levels related to diverse cytokines. In human keratinocytes inflamed by TNF-alpha, OP-D inhibited p38 and ERK protein activation and showed a reduction of NF-kappa B nuclear translocation. Furthermore, OP-D attenuated pro-inflammatory cytokine mRNA expressions in TNF-alpha-inflamed HaCaT cells. Accordingly, we came to the conclusion that OP-D is a potential natural drug which can be used in order to treat inflammatory skin diseases, such as AD. (C) 2019 Elsevier Inc. All rights reserved.