Cytokines are produced by the immunological, hormonal and nervous system cells. They consist of peptides and proteins affecting cell junctions and their mutual interactions. The role of cytokines in the central nervous system (c.n.s.) is complex. They not only control proliferation and differentiation of cells, but also participate in inflammatory reactions (becoming also a pathogenic factor), and in reparatory processes. The role of various types of cytokines is discussed as regards the occurrence of inflammatory reaction in the nervous tissue, immunological activation of glial cells, and determining the course of inflammatory diseases. Examples of the crucial role of cytokines in some inflammatory diseases are given.