There are many reasons for dark circles under the eyes, often related to genetics, endocrine metabolic disorders, adrenocortical dysfunction, systemic organ lesions or local microcirculatory disorders and other diseases. Congenital genetic or acquired increased pigmentation of the eyelids, aging and relaxation of the eyelids, skin wrinkling together resulting in the appearance of darker skin tone, depression of the inner lower part of the orbit forming a tear trough and thus forming a shadow, stagnant blood flow in the eyelid veins causing skin eye color deepening. Dark bags under the eyes are considered to be caused by frequent late nights, emotional instability, eye fatigue, too slow blood flow in aging veins, and insufficient oxygen supply to the red blood cells of the eye skin. The skin around the eye circle is thinner than normal skin, some people are born with fairer skin, the skin’s stratum corneum is thinner, the subcutaneous tissue is thin, which can hide the blood vessels under the eyes, the skin around the eye circle is greenish gray, some children can see the black eye circle. Dark circles under the eyes can also appear when the whole body is diseased. Some endocrine disorders such as hypothyroidism and Cushing’s syndrome can cause dark circles under the eyes. Some people also have dark circles under their eyes due to lack of qi and blood. Some people have frequent skin allergies, and skin allergies are treated with long-acting corticosteroids, which can form skin dependence on hormones and lead to local pigmentation, resulting in dark circles under the eyes. Other people have dark circles because of excessive eye fatigue, prolonged late nights, lack of sleep, excessive blood congestion in the eyes, and stagnant blood circulation. Dark circles under the eyes are related to genetics, skin characteristics, systemic diseases, allergies, medications, lack of sleep and a series of other problems, which require specific analysis.