Berkleylactone F is a major analogue of a family of recently described macrolide antibiotics, isolated from a mixed fermentation of two Penicillium species. Berkleylactone F is active against Gram-positive bacteria, Candida albicans and Candida glabrata, with an undescribed but purportedly novel mode of action. Berkeleylactone F is an analogue of A 26771B.