After a short description of the uses of pineapple as folk medicine by the natives of the tropics, the more important new pharmaceutical applications of bromelain, reported between 1975 and 1978, are presented. Although the exact chemical structure of all active components of bromelain is not fully determined, this substance has shown distinct pharmacological promise. Its properties include: (1) interference with growth of malignant cells; (2) inhibition of platelet aggregation; (3) fibrinolytic activity; (4) anti-inflammatory action; (5) skin debridement properties. These biological functions of bromelain, a non-toxic compound, have therapeutic values in modulating: (a) tumor growth; (b) blood coagulation; (c) inflammatory changes; (d) debridement of third degree burns; (e) enhancement of absorption of drugs. The mechanism of action of bromelain affecting these varied biological effects relates in part to its modulation of the arachidonate cascade.