Scientists are still unraveling the mystery of how exactly bromelain works, although it appears that bromelain works with several systems within the body. Studies on laboratory animals suggest that Bromelain works by decreasing bradykinin levels at the inflammatory site while causing a parallel decrease of the prekallikrein levels in sera. Bradykinin-degrading activity in sera was elevated after treatment with bromelain, although it was unchanged in the pouch fluid. These data indicate that bromelain inhibits plasma exudation through inhibiting the generation of bradykinin at the inflammatory site via depletion of the plasma kallikrein system. [13]

Bromelain may help the immune response by enhancing IFN-gamma-mediated nitric oxide and TNFalpha production by macrophages.