The chemical composition and antimicrobial activity of the essential oils obtained from the flowering aerial parts and ripe fruits of Echinophora spinosa L. (Apiaceae) from central Italy were analyzed by GC/MS. The major constituents of the oil from the aerial parts were beta-phellandrene (34.7%), myristicin (16.5%), delta3-carene (12.6%), alpha-pinene (6.7%) and alpha-phellandrene (6.2%), and of the oil from the ripe fruits p-cymene (50.2%), myristicin (15.3%), alpha-pinene (15.1%) and alpha-phellandrene (8.1%). The two oils showed good antimicrobial activity against Clostridium difficile, C. perfringens, Enterococcus faecalis, Eubacterium limosum, Peptostreptococcus anaerobius and Candida albicans with MIC values respectively of 0.25, 0.25, 0.25, 0.25, 2.25, and 0.50%, v/v, and 0.13, 0.13, 0.13, 0.13, 2.25, 0.50%, v/v, for aerial parts and ripe fruits respectively. A less significant antimicrobial activity against bifidobacteria and lactobacilli, very important in the intestinal microflora, was also detected, with MIC values higher than 4.0%, v/v.