Dear Sir, In a recent article we showed that correlation between histological indexes is strong for ulcerative colitis (UC). Due to the lack of intervention studies and the absence of a validated histological index, histological healing cannot be considered as a treatment goal in clinical practice for these patients. Pending these studies, we need to define the therapeutic goal for patients with UC. In the ACT 1 and 2 clinical trials, early mucosal healing defined by an endoscopic Mayo score (EMS) of 0–1 was associated with a lower risk of colectomy through 54 weeks of follow-up evaluation and better long-term outcomes related to symptomatic remission, corticosteroid-free symptomatic remission and corticosteroid use, and subsequent mucosal healing at weeks 30 and 54. With the exception of colectomy outcomes, an EMS of 0 at week 8 was associated with a greater proportion of patients with long-term clinical benefit. Among patients with clinical remission at week 8, an EMS of 0 versus 1 did not predict subsequent colectomy, symptomatic remission, corticosteroid-free remission or sustained mucosal healing. However, the duration of follow-up was too short, only 54 weeks, to show a statistically significant difference between an EMS of 0 and an EMS of 1 in terms of colectomy rates. In a French multicentre study, we previously showed that patients with refractory UC who achieved mucosal healing after infliximab initiation had better long-term outcomes, with significantly less colectomy and less infliximab failure after a median follow-up duration of 27 months. However, we did not compare an EMS of 0 with an EMS of 1. Using a well defined referral centrebased cohort, namely the Nancy IBD cohort, we investigated whether an EMS of 0 may be associated with better outcomes than an EMS of 1 in UC. Patients with an established diagnosis of UC were followed until January 2014. Survival curves were estimated by the Kaplan–Meier method and compared using a log rank statistic. Time to colectomy from the date of first endoscopic evaluation was calculated. Only patients with an EMS of 0 or 1 were included in the analysis. Of the 55 patients, 52.7% were women (n=29). The median age at diagnosis was 35.1 years. The mean age at first endoscopy was 40.7 years. According to the Montreal classification, 51% of patients had pancolitis, 32% had left-sided UC and 17% had proctitis. Eighteen patients (32.7%) had an EMS of 0 and 37 (67.3%) an EMS of 1 at first endoscopic evaluation after UC diagnosis. After a median follow-up of 48 months, 8 out of 55 patients (14.5%) underwent colectomy and all of them had an EMS of 1. Comparing survival curves (figure 1), an EMS of 0 was associated with less colectomy than an EMS of 1 (p=0.05). In conclusion, an EMS of 0 may predict a lower need for colectomy than an EMS of 1 in patients with UC. An EMS of 0 could define the minimum therapeutic goal for patients with UC to change disease course. Whether histological healing is the ultimate therapeutic goal for patients with an EMS of 0 will require further investigation.