This study compared the short-term effect of semi-elemental diet in treatment of active Crohn's disease with elemental diet which has been reported to be successful in inducing remission. The important differences between semi-elemental diet and elemental diet in composition are the form of nitrogen and fat content. Forty patients with active Crohn's disease were randomized to receive for 6 weeks either elemental diet (n = 21) which is composed of amino acid based with low fat content or semi-elemental diet (n = 19) which is oligopeptide-based and has higher fat content. Both groups showed similar improvement in Dutch-AI, Crohn's disease activity index (CDAI), erythrocyte sedimentation rate, C-reactive protein, serum albumin, body mass index and radiographic findings of bowel lesion. The present study suggests that semi-elemental diet is equal to elemental diet for treating active Crohn's disease. We conclude the compositional differences between the two diets did not affect the short-term effect of enteral nutritional therapy for active Crohn's disease.