Background: Malnutrition is a common problem in patients with digestive disease and is associated with impaired outcome. Objective: We investigated the effect of a three-month post-hospital nutritional intervention with high protein and energy supplements on body composition, muscle function and quality of life (QoL) in malnourished GI patients. Patients and intervention: Eighty malnourished patients with benign digestive disease were randomized to receive either oral nutritional supplements (ONS) for three months in addition to dietary counselling (DC) (ONS patients) or only dietary counselling (DC patients). Methods: Nutritional status was determined with the subjective global assessment, body composition by bioelectrical impedance and anthropometry, muscle function with hand-grip strength and peak flow. QoL was assessed by the 36-item short-form questionnaire. Results: Age, body cell mass (BCM), muscle function, gender distribution and QoL did not differ between ONS patients (n=38) and DC patients (n=42) at baseline. Body weight and BCM improved significantly in both groups after three months. However, hand-grip strength (26.1±11.3-31.5±10.1 kg, p<0.0001) and peak flow (329.2±124.0-388.9±108.4 l/min, p=0.004) improved only in the ONS patients and remained unchanged in the DC patients. Similarly, all eight scales of the QoL improved in the ONS patients compared with merely three in the DC patients. DC patients experienced significantly more readmissions (n=20) than ONS patients (n=10) during the study period (p=0.041). Conclusion: A three month intervention with high protein oral supplements improves outcome in malnourished patients with digestive disease in terms of functional status, QoL and rehospitalization.