This study investigates the role of *Faecalibacterium prausnitzii* in Crohn's disease (CD) and its potential as a probiotic. The researchers found that a reduction in *F. prausnitzii* levels in the ileal mucosa of CD patients is associated with a higher risk of postoperative recurrence of ileal CD. *F. prausnitzii* was shown to have anti-inflammatory effects in both in vitro and in vivo models of colitis. In vitro, *F. prausnitzii* reduced IL-12 and IFN-γ production and increased IL-10 secretion from peripheral blood mononuclear cells. In vivo, oral administration of live *F. prausnitzii* or its supernatant significantly reduced the severity of TNBS-induced colitis and tended to correct the dysbiosis associated with the colitis. These findings suggest that *F. prausnitzii* could be a promising probiotic for the treatment of CD.This study investigates the role of *Faecalibacterium prausnitzii* in Crohn's disease (CD) and its potential as a probiotic. The researchers found that a reduction in *F. prausnitzii* levels in the ileal mucosa of CD patients is associated with a higher risk of postoperative recurrence of ileal CD. *F. prausnitzii* was shown to have anti-inflammatory effects in both in vitro and in vivo models of colitis. In vitro, *F. prausnitzii* reduced IL-12 and IFN-γ production and increased IL-10 secretion from peripheral blood mononuclear cells. In vivo, oral administration of live *F. prausnitzii* or its supernatant significantly reduced the severity of TNBS-induced colitis and tended to correct the dysbiosis associated with the colitis. These findings suggest that *F. prausnitzii* could be a promising probiotic for the treatment of CD.