Objective. To determine the pattern of lymphocyte composition changes in Peyer's patches and peripheral lymph nodes in the development of experimental allergic encephalomyelitis (EAE) in mice without treatment and during fingolimod therapy. Material and methods. The research was performed on 40 inbred mice C57BI/6 which were stratified into two groups: mice with EAE of group 1 received no treatment, mice with EAE of group 2 were treated with fingolimod. Results. The development of EAE was accompanied by relative density increasing of lymphocytes, CD4, CD8-cells in Peyer's patches and peripheral lymph nodes that indicated the lymphoid tissue's active systemic response to EAE development. The fingolimod treatment of laboratory animals with EAE resulted in a more significant and prolonged increase in the relative density of lymphocytes, CD4 and especially CD8 cells in the lymphoid formations and also the development of less severe neurological symptoms that confirmed the efficacy of therapy. Conclusion. The intestinal lymphoid tissue may be actively involved in the development of autoimmune demyelinating process in the central nervous system.