Used primarily in the treatment of multiple sclerosis, particularly relapsing forms including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease. It helps reduce the frequency of clinical relapses and delays disability progression by modulating immune cell trafficking, limiting lymphocyte migration into the central nervous system. Also approved for moderate to severe ulcerative colitis, where it reduces inflammation and induces remission by targeting sphingosine 1-phosphate receptors on lymphocytes. Its oral formulation offers a convenient option for long-term management of these chronic inflammatory conditions.