Background: Biologics used to treat ulcerative colitis (UC) may lose their effect over time, requiring patients to undergo dose escalation or treatment switching, and systematic literature reviews of realworld evidence on these topics are lacking. Aim: To summarize the occurrence and outcomes of dose escalation and treatment switching in UC patients in real-world evidence. Methods: Studies were searched through MEDLINE, MEDLINE IN PROCESS, Embase and Cochrane (2006-2017) as well as proceedings from three major scientific meetings. Results: In total, 41 studies were included in the review among which 35 covered dose escalation and 12 covered treatment switching of biologics. Tumor necrosis factor antagonist (anti-TNF) escalation for all patients included at induction ranged from 5% (6 months) to 50% (median 0.67 years) and 15.2% to 70.8% (8 weeks) for anti-TNF induction responders. Mean/median time to dose escalation on anti-TNF ranged from 1.84 to 11 months. The most common switching pattern, infliximab ! adalimumab, occurred in 3.8% (median 5.6 years) to 25.5% (mean 3.3 years) of patients. Conclusions: Dose escalation and treatment switching of biologics may be considered as indicators of suboptimal therapy suggesting a lack of long-term remission and response under current therapies.