This study aimed to compare the absorption and tolerance of 20-g lactose loads as milk and yogurt in 17 patients with short-bowel syndrome with either a terminal jejunostomy (group A, n = 6) or a jejunocolic anastomosis (group B, n = 11). Records and measurements during the 8 h after the meals included fecal weight, symptoms, lactose and hexose flow rates in stomal effluents (group A), and breath-hydrogen excretion (group B). In group A lactose was better absorbed in the form of yogurt than in the form of milk (mean +/- SE: 76 +/- 6% vs 50 +/- 9%, P < 0.05), whereas no significant difference could be detected by using the breath-hydrogen test in group B. The excellent tolerance to 20 g lactose from milk and yogurt suggests that lactose should not be excluded from the diet of these subjects.