The data from this study shows that early-life antibiotic use may affect the progression of subsequent disease conditions by changing host microbiota and immunologic development. For this study, they used a murine model of dextran sodium sulfate (DSS)-induced colitis and evaluated the effect on disease outcomes of early-life pulsed antibiotic treatment (PAT). The dataset includes 16S sequencing data. They evaluated microbiota effects at the 16S rRNA gene level and intestinal T cells by flow cytometry. This study showed that a single PAT early-in-life worsened later DSS-induced colitis by disturbing the microbial community and changing mucosal immune cell composition.