Dark circles are used to describe the gray state around the eyes, giving a fatigued, sad or hangover-like appearance and bringing cosmetic troubles. Although dark circles are very common, however, the literature on dark circles is less reported. This article summarizes the etiology, diagnosis and treatment of dark circles by reviewing the medical literature related to dark circles and combining the authors’ clinical experience in the diagnosis and treatment of dark circles. Dark circles are the result of multiple factors and can be divided into three main types: pigmented dark circles (excessive deposition of dermal melanin), vascular dark circles (the thin and transparent skin of the eyelids, the orbicularis oculi muscle underneath and the blood vessels contained therein, the dermal capillary network and the subcutaneous blue reticular veins through the skin to form a gray appearance), and structural dark circles (congenital and acquired structural shadows), which can be combined with the above in different patients. Different patients can have a combination of the above types, called mixed dark circles. The treatment needs to be based on the different causes, and the corresponding treatment methods such as depigmentation, chemical peeling, laser, injection filling, oculoplastic surgery, etc. Mixed dark circles require combined treatment to achieve cosmetic results.