The preventive and therapeutic mechanisms in multiple sclerosis are not clearly understood. We investigated whether Hyungbangpaedok-san (HBPDS), a traditional herbal medicine, has a beneficial effect in experimental autoimmune encephalomyelitis (EAE) mice immunized with myelin oligodendrocyte glycoprotein peptide (MOG 35-55). Onset-treatment with 4 types of HBPDS (extracted using distilled water and 30%/70%/100% ethanol as the solvent) alleviated neurological signs, and HBPDS extracted within 30% ethanol (henceforth called HBPDS) was more effective. Onset-treatment with HBPDS reduced demyelination and the recruitment/infiltration and activation of microglia/macrophages in the spinal cord of EAE mice, which corresponded to the reduced mRNA expression of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), iNOS, and chemokines (MCP-1, MIP-1α, and RANTES) in the spinal cord. Onset-treatment with HBPDS inhibited changes in the components of the blood-brain barrier such as astrocytes, adhesion molecules (ICAM-1 and VCAM-1), and junctional molecules (claudin-3, claudin-5, and zona occludens-1) in the spinal cord of EAE mice. Onset-treatment with HBPDS reduced the elevated population of CD4+, CD4+/IFN-γ+, and CD4+/IL-17+ T cells in the spinal cord of EAE mice but it further increased the elevated population of CD4+/CD25+/Foxp3+ and CD4+/Foxp3+/Helios+ T cells. Pre-, onset-, post-, but not peak-treatment, with HBPDS had a beneficial effect on behavioral impairment in EAE mice. Taken together, HBPDS could alleviate the development/progression of EAE by regulating the recruitment/infiltration and activation of microglia and peripheral immune cells (macrophages, Th1, Th17, and Treg cells) in the spinal cord. These findings could help to develop protective strategies using HBPDS in the treatment of autoimmune disorders including multiple sclerosis.