Atopic dermatitis is epidermal hyperplasia, skin barrier dysfunction, and the aberrant activation of immune cells. Janus kinase (JAK) is a family of cytoplasmic nonreceptor tyrosine kinases that consists of four members, such as JAK1, JAK2, JAK3, and TYK2. The JAK signaling pathway plays a critical role in a wide range of autoimmune and inflammatory diseases, including atopic dermatitis. Abrocitinib is an orally bioavailable and selective JAK1 inhibitor, and it was approved in January, 2022, for the treatment of atopic dermatitis. The chemical structure and physical properties of abrocitinib, its synthesis, mechanism of action, and pharmacokinetic profile are summarized.