Glucagon-like peptide-1 (GLP-1) is a gastrointestinal (GI) hormone secreted in response to feeding by enteroendocrine L cells located predominantly in the lower small intestine and large intestine. GLP-1 inhibits the secretion and motility of the upper gut and has been suggested to play a role in the "ileal brake". In this study, we investigated the effect of recombinant GLP-1 (7-36 amide) (rGLP-1) on lipid absorption in the small intestine in intestinal lymph duct cannulated rats. In addition, the effects of rGLP-1 on intestinal production of apolipoprotein (apo) B and apo A-IV, two apolipoproteins closely related to lipid absorption, were evaluated. rGLP-1 was infused through the jugular vein and lipids infused through duodenal cannula simultaneously. Our results showed that 20 pmol/kg/min rGLP-1 caused a dramatic and prompt decrease in lymph flow from 2.22 ± 0.15 (means ± SE, n = 6) ml/h at baseline to 1.24 ± 0.06 ml/h at the 2nd h (P < 0.001). In contrast, a significant increase in lymph flow was observed in the saline (control) group (2.19 ± 0.20 ml/h at baseline and 3.48 ± 0.09 ml/h at the 6th h of lipid infusion, P < 0.001). rGLP-1 also inhibited intestinal triolein absorption (P < 0.05) and lymphatic apo B and apo A-IV output (P < 0.05), but did not affect cholesterol absorption. In conclusion, rGLP-1 dramatically decreases intestinal lymph flow, and reduces triglyceride absorption and apo B and apo A-IV production. These findings suggest a novel role for GLP-1 in lipid absorption.