Background/Aims: Exacerbating factors of ulcerative colitis (UC) are multiple and complex with individual influence. We aimed to evaluate the efficacy of disease control by searching and restricting inflammation trigger factors of UC relapse individually in daily clinical practice. Methods: Both patients with UC history or new diagnosis were asked to avoid dairy products at first doctor visit. Individual-reported potential trigger factors were restricted when UC flared up (Mayo endoscopy score ≥1) from remission status. The remission rate, duration to remission and medication were analyzed between the groups of factor restriction complete, incomplete and unknown. Results: The total remission rate was 91.7% of 108 patients with complete restriction of dairy product. The duration to remission of UC history group was significantly longer than that of new diagnosis group (88.5 days vs. 43.4 days, P=0.006) in patients with initial endoscopic score 2–3, but no difference in patients with score 1. After first remission, the inflammation trigger factors in 161 relapse episodes of 72 patients were multiple and personal. Milk/dairy products, herb medicine/Chinese tonic food and dietary supplement were the common factors, followed by psychological issues, non-dietary factors (smoking cessation, cosmetic products) and discontinuation of medication by patients themselves. Factor unknown accounted for 14.1% of patients. The benefits of factor complete restriction included shorter duration to remission (P<0.001), less steroid and biological agent use (P=0.022) when compared to incomplete restriction or factor unknown group. Conclusions Restriction of dairy diet first then searching and restricting trigger factors personally if UC relapse can improve the disease control and downgrade the medication usage of UC patients in daily clinical practice.