Objective To study the inhibition effect of non custodial terpenes-3β-alcohol to experimentally in-duced autoimmune encephalomyelitis in guinea pigs. Methods Different doses (25 mg/kg, 50 mg/kg and 100 mg/kg) of non custodial terpenes-3β-alcohol were given to the experimentally induced autoimmune encephalomyelitis model of guinea pigs by gavage for 8 weeks. Plasma levels of CD4+/CD8+, IL-1, IL-2, IL-6, IL-10, neuropeptide Y (NPY), beta endorphin (β-EP) , transforming growth factor-β(TGF-β), matrix metalloproteinase (MMP-2), nitric oxide synthase (NOS) and leuko-cyte differentiation antigen CD3 were assessed. The brain neuron morphology changes was observed under light microscopy while its ultrastructure changes was observed under electron microscope. NOS expression in neurons was observed through immunofluoresce technology. Results Non custodialterpenes-3β-alcohol inhibited the increase of plasma CD4+/CD8+, IL-1, IL-2, IL-6, IL-10, MMP-2, CD3 and NPY while decrease of plasmaβ-EP, brain TGF-β. It also increase NOS expres-sion in neuronal cytoplasm and maintained neuron morphology. Conclusion Non custodial terpenes-3β-alcohol inhibit-ed the experimental autoimmune encephalomyelitis in guinea pig.