Bromelain is a crude extract from the pineapple that contains, among other components, various closely related proteinases, demonstrating, in vitro and in vivo, anti-edematous, anti-inflammatory, antithrombotic, and fibrinolytic activities. The active factors involved are biochemically characterized only in part.
Due to its efficacy after oral administration, its safety, and lack of undesired side effects, bromelain has earned growing acceptance and compliance among patients as a phytotherapeutical drug. Recent results from preclinical and pharmacological studies recommend bromelain as an oral drug for complementary tumor therapy: “Bromelain acts as an immunomodulator by raising the impaired immunocytotoxicity of monocytes against tumor cells … modulation of immune functions, its potential to eliminate burn debris and to accelerate wound healing. Topical bromelain (35% in a lipid base) has achieved complete debridement on experimental burns in rats” (Source: Cellular and Molecular Life Sciences, August 2001).
There is a good deal of research supporting oral use of bromelain, particularly to reduce edema and inflammation (Source: Phytomedicine, December 2002, pages 681–686).
The research about bromelain is related to oral consumption and animal studies. Theoretically, bromelain breaks down the connecting structure that holds surface skin cells together, which causes exfoliation but can also cause irritation. However, exactly how much bromelain is needed (the amount used in skin-care products is typically less than 1%), whether it is stable as used in cosmetics, and in what bases and pH it works best have not been established. There is little to no research demonstrating how bromelain reacts on skin.