Provided is a novel agent for the prevention and/or treatment of Pseudomonas aeruginosa infection. It was discovered that bacteria belonging to the genus Enterococcus can prevent and/or treat Pseudomonas aeruginosa infection. An agent for the prevention and/or treatment of Pseudomonas aeruginosa infection, the agent containing bacteria belonging to the genus Enterococcus. A medicine for the prevention and/or treatment of Pseudomonas aeruginosa infection, the medicine containing bacteria belonging to the genus Enterococcus. A food for the prevention and/or treatment of Pseudomonas aeruginosa infection, the food containing bacteria belonging to the genus Enterococcus.