Preprint Remitting-relapsing multiple sclerosis is now considered a treatable disease thanks to disease modifying treatments with good efficacy of reducing relapses. In contrast, effective treatment of progressive multiple sclerosis remains elusive. Using a murine experimental autoimmune encephalomyelitis (EAE) model, this study showed that acid treatments at early stages of EAE attenuated disability progression to advanced stages. When acid treatments were initiated prior to the onset of disease, onset of EAE was prevented or delayed. Histological analysis showed that the acid treatments cleared inflammation in the spinal cords. These results suggest that all forms of multiple sclerosis could be effectively prevented or treated with pH modifiers such as acids.