Most moisturizers on the market are treated as cosmetics. But, according to medical regulation in Korea, only pharmaceuticals and medical devices can be recommended for treatment of skin diseases. However, a daily moisturizers are recommended by dermatologists as an important part of the management of patients with atopic dermatitis and other dry skin diseases. Cosmetics may contain allergens and some formulations also deteriorate skin barrier function, with possible negative effects on the skin. Not surprisingly, more detailed and scientific data on the potential effects and side effects of moisturizers and cleansers have been needed. In addition, more knowledge about cosmetics was requested for dermatologists. In the present overview, the effects of moisturizers and cleansers on skin dryness, barrier function, and prevention of dermatitis and medically important ingredients are briefly discussed.