The present invention relates to vesicles derived from Faecalibacterium prausnitzii and to uses thereof. It has been experimentally confirmed by the present inventors that the vesicles in the clinical samples of patients with gastric cancer, colorectal cancer, liver cancer, pancreatic cancer, cholangiocarcinoma, ovarian cancer, bladder cancer, lymphoma, myocardial infarction, atrial fibrillation, and Parkinson's disease were significantly reduced in comparison with a normal person and that when vesicles separated from the strain were administered, the secretion of inflammatory mediators caused by pathogenic vesicles, such as vesicles derived from colon bacilli, was significantly inhibited. The vesicles derived from Faecalibacterium prausnitzii according to the present invention are expected to be usefully employed for the purposes of developing a method for diagnosing gastric cancer, colorectal cancer, liver cancer, pancreatic cancer, cholangiocarcinoma, ovarian cancer, bladder cancer, lymphoma, myocardial infarction, atrial fibrillation, and/or Parkinson's disease, and a composition for preventing, alleviating, or treating said diseases.La présente invention concerne des vésicules issues de Faecalibacterium prausnitzii et des utilisations associées. Il a été confirmé expérimentalement par les présents inventeurs que la proportion des vésicules a été significativement réduite dans des échantillons cliniques provenant de patients atteints d'un cancer gastrique, d'un cancer colorectal, d'un cancer du foie, d'un cancer du pancréas, d'un cholangiocarcinome, d'un cancer de l'ovaire, d'un cancer de la vessie, d'un lymphome, d'un infarctus du myocarde, d'une fibrillation auriculaire, et de la maladie de Parkinson par comparaison avec une personne normale et que les vésicules, après administration, une fois séparées de la souche, inhibent significativement la sécrétion de médiateurs inflammatoires provoquée par des vésicules pathogènes, telles que des vésicules issues de ba
