The present study focuses on the digestion and absorption of milk and fermented milk (FM) reflected by gastro-ileal N and electrolyte movements in six healthy volunteers. The N and electrolyte content of the intestinal effluents were analysed both at the beginning of the jejunum and in the distal ileum. The gastric half-emptying time of the liquid phase was significantly (P < 0.05) shorter for milk (35 (SE 2) min) than for FM (60 (SE 2) min). The N balance showed that 58 and 50% of ingested proteins, milk and FM respectively were absorbed between the stomach and the proximal jejunum and that 91 and 90% respectively were absorbed between the stomach and the terminal ileum in 240 min. Evaluation of mineral absorption indicated that 44 and 67% of Ca was absorbed in the duodenum after milk and FM ingestion respectively, and 41 and 11% of Ca disappeared between the jejunum and the ileum respectively. With regards to N and Ca intestinal availability, the present study confirms that FM products represent an interesting source of N as well as minerals for man. This confers on FM a beneficial effect compared with milk especially for lactase (EC 3.2.1.108)-deficient subjects and children with persistent diarrhoea.