Mast cells (MCs) are present in the skin and mucous membranes, lymphoid organs, intestine wall, and brain, where they are located close to blood and lymphatic vessels and nerve terminals. As a source of a large number of biologically active substances, many of which are released quickly into the environment as a result of degranulation process, mast cells play an essential role in the regulation of physiological processes in the tissues where they are present. Changes in the MC population and activity in tissues during aging is associated with age-related changes of the skin and mucous membranes, as well as the development of centralnervous- system disorders such as itching, headache, joint and muscle pain, memory loss, attention deficit, depression, anxiety and depressive disorders, autism, Alzheimer’s disease, and multiple sclerosis.