SummaryAlthough normal epidermal barrier function depends on numerous factors, including corneocytes, lipids, enzymes, pH, and calcium gradient, the key players are lipids and proteins in the stratum corneum. Atopic dermatitis is characterized by barrier abnormalities, such as the presence of filaggrin mutations in almost 50% of patients with moderate/severe atopic dermatitis, and lipid disturbances, mainly expressed as insufficient ceramides. In this review, with an emphasis on human studies, we consider the latest research on ceramides, on ceramides in different types of eczema and following various types of treatment. We also consider the genetic influence on stratum corneum lipids. The review is an update on research indexed in PubMed following the discovery of the filaggrin mutations in atopic dermatitis in 2006, but when newer publications cannot stand alone, we include publications from before 2006.