BACKGROUND: Tofacitinib is an oral small molecule Janus kinase inhibitor for the treatment of ulcerative colitis. AIM: To report efficacy and infection rates in patients receiving tofacitinib induction treatment, by baseline corticosteroid status. METHODS: We evaluated efficacy and safety data from OCTAVE Induction 1&2 in patients with moderately-to-severely active ulcerative colitis who received tofacitinib 10 mg twice daily or placebo for 8 weeks, based on induction baseline oral corticosteroid use (Corticosteroid-Yes/No) and dose (< 20/ >/= 20 mg/day). Infections of interest included serious infections, herpes zoster (HZ), and adjudicated opportunistic infections (OIs). RESULTS: At OCTAVE Induction 1&2 baseline, 478/1092 (43.8%) patients were receiving corticosteroids. Tofacitinib demonstrated significant induction efficacy versus placebo for both Corticosteroid-Yes and Corticosteroid-No. With adjustment for prior tumor necrosis factor inhibitor and immunosuppressant failure, there were no statistically significant differences in remission and clinical response rates for Corticosteroid-Yes versus Corticosteroid-No. Among tofacitinib-treated patients, HZ and OIs occurred more frequently in Corticosteroid-Yes versus Corticosteroid-No, regardless of dose (< 20 mg vs. >/= 20 mg). Infection incidence rates (regardless of severity/seriousness) during tofacitinib induction were generally similar regardless of baseline corticosteroid use. The proportion of tofacitinib-treated patients with HZ was 0.2% for Corticosteroid-No versus 1.1% for Corticosteroid-Yes < 20 mg and 1.0% for Corticosteroid-Yes >/= 20 mg. Two out of three patients had HZ OIs. CONCLUSIONS: Tofacitinib induction efficacy (clinical response and remission) was similar in baseline corticosteroid subgroups. Infections of interest were rare; HZ and OIs occurred more frequently among those receiving tofacitinib and corticosteroids versus those receiving tofacitinib without corticosteroids. TRIAL REGISTRATION: http://www. CLINICALTRIALS: gov (NCT01465763[21/10/2011]; NCT01458951[21/10/2011]).