Pure cultures of one Philippine strain each of the myxobacteria Chondromyces apiculatus and Pyxicoccus fallax were characterized developmentally and grown in the fermentation medium Amb lm for the production of their secondary metabolites. The rotavaporated methanolic extracts from the fermentation brew for either species yielded six possible compounds based on their Rf values in TLC chromatograms. However, only the possible epothilon from Pyxicoccus fallax exhibited limited growth inhibition of test pathogenic microorganisms both in the bioassay by the Kirby-Bauer method and bioautography. The yeast Candida albicans and the bacteria Pseudomonas aeruginosa and Bacillus cereus var. mycoides were inhibited but not strains of Escherichia coli, Staphylococcus aureus, Bordetella brochiseptica, and Nocardia sp. In plate culture, P. fallax and Cladosporium sp. exhibited mutual antagonism, a phenomenon heretofore unreported in the literature between any myxobacterium and a fungus.