Eriksson C, et al. - This study examined the effect of thiopurines as a maintenance therapy in ulcerative colitis (UC), with regard to colectomy, hospital admission, progression in disease extent and anti-tumour necrosis factor (TNF) therapy within 10 years from initiation. Eligible candidates included patients diagnosed with UC within the Orebro University Hospital catchment area, during 1963–2010, who initiated thiopurines. It was observed that the cumulative probability of colectomy within 10 years was 19.5% in the tolerant patients compared with 29.0% in intolerant. Additionally, the probability of hospital admission was 34.0% in the tolerant vs 56.2% in intolerant patients. Thus, it was deduced that thiopurines exerted a profound beneficial impact on the natural history and long-term colectomy rates of UC.