We compared the absorption of carbohydrate from solutions of glucose oligomers and glucose in jejunal Thiry-Vella fistulae, a preparation deprived of pancreatic secretions. The studies were performed with two concentrations (90 and 360 mg/dl) of both glucose and the glucose oligomers. Carbohydrate absorption from glucose solutions (33.1 × 2.8, 115.9 × 8.9 μg/cm/min) was significantly greater (P< 0.025;P< 0.005) than that from oligomer solutions (26.6 × 2.1 and 92.4 × 9.0 μg/cm/min). Thin-layer analyses of the perfusates demonstrate digestion of oligomers with a chain length up to eleven and suggest digestion of oligomers of even greater chain length. Atrophy of the jejunal mucosa occurred over the course of the study as evidenced by a decrease in the ratio of villous height to crypt depth from 3.8 to 0.3, and by a 80% decrease in the activity of maltase, sucrase, and lactase. Atrophy was accompanied by a significant decline in the absorption of both glucose oligomers (P< 0.005) and glucose (P< 0.01) from the more concentrated solutions but the decrement in absorption of both carbohydrates was similar, glucose oligomers, 79.3 × 19.4 μg/cm/min; and glucose, 69.8 × 14 μg/cm/min (P> 0.20). Water absorption was enhanced by both carbohydrates, but there was no demonstrable difference between solutions of glucose and glucose oligomers. The osmolality of the solutions clearly influenced water absorption (P< 0.025) but failed to effect the absorption of carbohydrates.