OBJECTIVE: For decades, the determination of changes in splanchnic blood flow and oxygen uptake after a meal has been used in the management of patients with suspected chronic intestinal ischaemia. However, little is known about the normal meal-induced responses. The aim of the present study was therefore to measure the splanchnic blood flow and oxygen uptake before and after a standardized meal in a group of middle-aged normal volunteers. MATERIAL AND METHODS: Splanchnic blood flow and oxygen uptake were determined at baseline and after a 3600-kJ mixed meal in 8 healthy women (50-70 years) and 10 healthy men (52-76 years). Splanchnic blood flow was measured during hepatic vein catheterization by indirect Fick principle with indocyanine green as the indicator. Splanchnic oxygen uptake was calculated from splanchnic blood flow and the arteriovenous oxygen difference. RESULTS: The meal induced a significant peak increase in splanchnic blood flow of 0.60 (0.26-1.07) l x min(-1) (mean, range) from a baseline level of 1.05 (0.66-1.33) l x min(-1). Splanchnic oxygen uptake showed a significant peak increase of 1.40 (0.44-4.13) mmol x min(-1) from a baseline level of 2.18 (1.41-3.31) mmol x min(-1). A close association was found between the meal-induced peak increases in splanchnic blood flow and oxygen uptake, but the variables were not related to gender or body surface area of the subjects. CONCLUSIONS: A 3,600-kJ mixed meal induces a significant increase in splanchnic blood flow and oxygen uptake in middle-aged healthy humans. Our data may be relevant for the evaluation of corresponding data from patients with suspected chronic intestinal ischaemia.