Neuregulin 4 (NRG4) is a kind of protein containing epidermal growth factor (EGF)-like domains, mainly expressed and secreted by brown adipocytes. It specifically activates EGF receptor ErbB4 (v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 4) to stimulate cell proliferation, inhibit apoptosis and improve energy metabolism of cells. Increasing evidence has shown that NRG4 plays an important role in epithelial cell-related diseases, cardiovascular diseases, tumors and glycolipid metabolic diseases, and therefore it could be a potential therapeutic target of some diseases.