The mechanism for chrysodin antifungal action was studied by using Candida albicans. Chrysodin inhibited the incorporation of radioactive precursors into macromolecules in whole cells nonspecifically among various macromolecule species, i.e., DNA, RNA, protein, polysaccharide and lipid. It also inhibited cellular respiration with a more marked effect on exogenous than on endogenous respiration. On the other hand, chrysodin greatly enhanced the leakage of UV-absorbing materials from treated cells, although it had no effect on liposomal glucose leakage. Cells grown in the presence of low concentrations of chrysodin had significantly lower amounts of linolenic acid and linoleic acid than control cells. The addition of unsaturated fatty acids reversed to some extent the growth inhibition by chrysodin. These results suggest that the antifungal action of chrysodin is due to a change in the cell membrane permeability related to polyenoic fatty acid biosynthesis in the yeast cells. © 1990 by the Japan Society for Bioscience, Biotechnology, and Agrochemistry.