Gut microbial dysbiosis and altered metabonomics have been implicated in the pathogenesis of Crohn's disease (CD). The aim of our study was to characterize the gut microbiome structure and metabolic activities in pediatric CD patients with different clinical outcomes after infliximab (IFX) therapy. Fecal samples were collected from 20 healthy children and 29 newly diagnosed pediatric CD patients. 16S rRNA/ITS2 gene sequencing and targeted metabolomics analysis were applied to profile the gut bacterial microbiome, mycobiome, and metabolome, respectively. Pediatric CD patients exhibited lower relative abundances of short-chain fatty acids (SCFAs)-producing bacteria including 