The root bark of Pleiospermium alatum afforded five alkaloids, five coumarins, lupeol and stigmasterol. One of the acridones, 1,5,6-trihydroxy-2,3-dimethoxy-10-methyl-9-acridone is a new compound while another, 1-hydroxy-2,3,5,6-tetramethoxy-10-methyl-9-acridone, is a new natural product. Chemotaxonomic aspects of the occurrence of acridone and coumarins in Pleiospermium is discussed. Seselin, one of the coumarins encountered displayed significant antifungal activity against Cladosporium cladosporioides. © 1990.