A severe nutritional deficiency status is described in a 22-year-old patient with Crohn's disease. The clinical picture on admission was dominated by an episode of gastrointestinal bleeding secondary to clotting disturbances (vitamin K deficiency) and severe cachexia due to a protein energy malnutrition. The mechanisms of severe nutritional disturbances in Crohn's disease are multifactorial. In this patient, lymphatic leakage into the intestinal lumen was a major contributing factor in the pathogenesis of protein-losing enteropathy, fat malabsorption, and lymphocytopenia. The authors were able to demonstrate this intestinal lymph loss by nuclear imaging.