The natural barrier of the skin is a “brick wall structure” consisting of “lipids” and “natural moisturizing factors” between the cells of the stratum corneum and the cells, with a The “sebaceous membrane”, which together form a natural protective barrier for the body. This is the famous “brick wall theory” proposed by Peter in 1983. The barrier of epidermis is very important for human health, and its function is divided into two aspects: first, to prevent and keep the human skin from losing water, i.e. moisturizing function (of course, at the same time, to prevent external moisture from entering the human body easily); second, to prevent bacteria, fungi and viruses on the surface of the skin from entering the human body and causing diseases. Changjing, Department of Dermatology, Affiliated Hospital of Inner Mongolia University for Nationalities Therefore, when the barrier function of the skin is destroyed, not only the moisturizing function of the skin decreases; at the same time, it can also aggravate many immune-related skin diseases such as eczema, atopic dermatitis and psoriasis. This establishes a theoretical basis for how skin lesions (such as those caused by scratching) and infections can lead to inflammatory skin diseases, and how patients with inflammatory skin diseases can prevent and treat skin diseases by protecting the skin barrier, by avoiding infections, and by avoiding skin breakage. The skin is the largest organ of the human body, accounting for 16% of body weight, but the main component of this largest organ is water. It can be said that the skin is a “water reservoir”. The maintenance of normal skin moisture is not only the basis of skin appearance and moisturization, but also the basis of maintaining normal physiological functions of the skin. When the skin barrier function is damaged due to skin diseases, the use of moisturizers can restore and maintain the barrier function of the skin, which is an auxiliary treatment for the disease and prevent recurrence, because good moisturizers have a complementary effect on the “sebaceous membrane”, and the moisturizing factors and lipids in the moisturizers can immediately penetrate into the epidermal keratin-forming cells, so that the damaged “brick” cells can be replaced by the skin. The damaged “brick wall structure” can be gradually repaired.