Backgrounds and aims: Total parenteral nutrition (TPN) has been traditionally used as an adjunctive therapy in severe ulcerative colitis patients. We performed a prospective study to ascertain the safety, nutritional efficiency, tolerance and costs of total enteral nutrition in this situation. Methods: After 48 hours of intensive medical treatment, severe ulcerative colitis patients initiated enteral feeding with a polymeric formula. The formula concentration and volume were increases daily. Results: 17 patients (7 women, 10 men; age 36,8+/-12,8 years) with a mean clinical activity score of 15,6+/-1,5 were included. In 14 patients (82,4%) enteral nutrition was well tolerated, attaining in 11 of them more than 80% of the caloric requirements by day 4. In 3 cases we observed vomiting and bloating. Prealbumin levels improved significantly from 11,1+/-3,4 mg/dl to 22,7+/-6,8 mg/dl (p = 0.002) at the end of enteral nutrition (11,8+/-4,7 days). Albumin and other nutritional parameters did not change. Conclusion: total enteral nutrition could be considered a safe and well tolerated nutritional support in these patients. Although albumin and other nutritional parameters did not change during the study period, the increase in prealbumin levels suggests a favourable anabolic effect of total enteral nutrition.