A pharmacological survey of flora of the Palumarainforest including 90 species representing 19 families has been carriedout. Crude plant extracts have been screened for cytotoxic, antibacterial,antifungal, and antiviral activity, as well as brine shrimp lethality. Ofthese, 27 extracts exhibited remarkable cytotoxic activity, 23 showed antimicrobialactivity, and 7 showed promising antiviral activity. Thus, 53 of the plantspecies examined showed marked bioactivity in one or more bioassays; a "hitrate" of 59%. These results underscore the phytomedicinal potentialof Australian tropical rainforests.