Xanthochymol and garcinol, isoprenylated benzophenones purified from Garcinia xanthochymus fruits, showed multiple activities against fungal biofilms. Both compounds effectively prevented emergence of fungal germ tubes and were also cytostatic, with MICs of 1 to 3 ΞM. The compounds therefore inhibited development of hyphae and subsequent biofilm maturation. Xanthochymol treatment of developing and mature biofilms induced cell death. In early biofilm development, killing had the characteristics of apoptosis. These activities resulted in failure of biofilm maturation and hyphal death in mature biofilms. In mature biofilms, xanthochymol and garcinol caused the death of biofilm hyphae, with 50% effective concentrations (EC50s) of 30 to 50 μM. Additionally, xanthochymol-mediated killing was complementary with fluconazole against mature biofilms, reducing the fluconazole EC50 from greater than 1,024 μg per ml to 13 μg per ml.