We recently reported in your journal the discovery of an anti-inflammatory protein produced by Faecalibacterium prausnitzii, a commensal bacterium involved in Crohn’s disease (CD) dysbiosis. 1 We wish to highlight and complete these recent data. The involvement of the intestinal microbiota in the pathogenesis of CD is well recognised. It has been shown that dysbiosis (an imbalance in the composition of the intestinal microbiota) could participate in chronic and inappropriate activation of the intestinal immune system and lead to inflammation. Dysbiosis is characterised by a deficiency of certain bacteria, such as