Commonly called pimples or zits and universally disdained by teenagers and adults alike, acne occurs when skin follicles get blocked by the oil or sebum that normally drains to the surface of the skin. Sebum secretions increase with hormonal changes, especially around puberty, pregnancy, and menopause, and when the sebum is blocked it allows bacteria and yeast to grow, causing the skin to become inflamed and eventually resulting in acne.

The severity of the infection defines the characteristics of the acne. Whiteheads are secretions trapped beneath the skin; blackheads are the sebum breaking through the skin, colored black as a result of the body's natural pigment deposits; and cystic acne is characterized by severe pus-filled infections under the skin, which can be painful. Medical conditions like polycystic ovarian syndrome and adrenal or pituitary gland tumors also can cause acne. In severe cases, acne can lead to permanent scars.

In Chinese medicine, the skin is controlled by the lungs; acne is commonly a sign of pathogenic heat in the lungs and intestines. So the Chinese approach to treating acne is to cool the heat, cleanse the lungs, detoxify the intestines, and externally heal the condition.