The exaggerated inflammatory response in inflammatory bowel disease (IBD) is under circadian rhythm control and peaks at night. We therefore hypothesized that intravenous infliximab would be more effective when administered before peak inflammatory response. This retrospective, proof-of-concept study assessed clinical (hospitalization/surgery) and biochemical (CRP, albumin) outcomes in 113 adult IBD patients who received inpatient infliximab, grouped into "late" (18:00 h-00:00 h) and "early" (12:00 h-18:00 h) administration. Demographics and disease characteristics were similar between groups. While the "late" group had only marginally higher 30 d surgery and readmission rates (9.38% versus 7.41% and 9.38% versus 8.64% respectively), the difference was more notable for women (15.38% versus 11.11% and 15.38% versus 8.33% respectively). "Early" had higher 72 h CRP response (83% versus 71%) and significant improvement in 40 d CRP compared to "late" ( = 0.0006). Albumin worsened in "late" versus "early" at 7 d (-17% versus +8%) but improved in both at 30 d (+16% versus +29%) compared to baseline. Therefore, "early" infliximab appears to be associated with 1) lower 30 d surgery/readmission rates, 2) higher 72 h CRP response, 3) improved 40 d CRP trend, and 4) favorable change in albumin at 7 d and 30 d compared to "late," suggesting that administration pre-peak inflammatory response (i.e. before 18:00 h) might enhance inflammatory control with improved outcomes. p