The lecture deals with the differential diagnosis and treatment of diseases accompanied by itching. It considers the major components of its pathogenesis, which are important to provide a rationale for its therapy. Particular emphasis is laid on the analysis of the most common classifications of the causes of itching, which take into account both pathogenetic and clinical parameters. The main differentially diagnostic signs of dermal and nondermal diseases attended by itching are given. Antihistamines among the agents intended for itching therapy are considered in detail. The efficacy and safety of first- and second-generation antihistamines, including quinuclidine derivatives, are comparatively analyzed.