Suplatast tosylate is a Th2 cytokine inhibitor that attenuates IL-2, IL-5 and IL-13 production and has no effect on IFN-γ production. Acts as an immunoregulator that suppresses IgE production, eosinophil infiltration and histamine release. Shows antiasthmatic, anti-inflammatory and antifibrotic activity in vivo. Suplatast Tosilate (ST) is an innovative anti-allergic medication that has emerged in recent years. It is a synthetic compound known as the l-tosylate ester of suplatast, which is a novel anti-allergic substance. Suplatast Tosilate can hinder the production of pro-inflammatory cytokines, including interleukin-4 and interleukin-5. Moreover, it has also been found to suppress the activity of enzymes involved in generating inflammatory mediators such as cyclooxygenase-2 and phospholipase A2.