Bergapten (BP), derived from Cnidium monnieri (L) Cusson, is an ingredient widely used in traditional Chinese medicine and has important biological and pharmacological activities. However, the effect of BP on ovariectomy-induced osteoporosis and the underlying mechanism are not entirely clear. In this study, we investigated the effects of BP on ovariectomy-induced osteoporosis and receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclastogenesis in vivo and in vitro, and explored the underlying mechanism. We found that BP treatment exerted beneficial effects on ovariectomy-induced osteoporosis in vivo. Further, BP attenuated osteoclastogenesis in bone marrow macrophages (BMMs) and RAW264.7 cells without any cytotoxicity. Additionally, BP specifically inhibited RANKL-induced NF-KB and JNK signaling,but did not suppress p38 and ERK. At the mRNA level, BP inhibits the OC-associated transcription factor NFATcl and c-fos, thereby affecting the expression of OC differentiation-related genes. Moreover, BP disrupted the formation of F-actin rings, which are important for bone-resorbing activity, and impairs OC bone resorption. Therefore, BP may be a useful alternative therapy for postmenopausal osteoporosis. (C) 2018 Elsevier Inc. All rights reserved.