Ambuic acid is a cyclohexanone that has phytopathogenic antifungal, quorum sensing inhibitory, and antibacterial activities. Ambuic acid inhibits the biosynthesis of cyclic peptides involved in quorum sensing, including gelatinase biosynthesis-activating pheromone (GBAP) in E. faecalis, autoinducing peptide I (AIP-I) in S. aureus, and LsrD698 and LsrD826 in L. innocua. It suppresses abcess formation in a mouse model of skin infection induced by methicillin-resistant S. aureus (MRSA) when administered at a dose of 5 µg and decreases the activity of the agr quorum sensing system in an in vivo reporter assay.