AIM To investigate the effect of DO C(deoxycholic acid) on the absorption of INS-PLA-NP[insulin-loaded poly(lactic acid) nanoparticles] in different sites of gastrointestinal tracts. METHODS After INS-PLA-NP that contained or did not contain DOC was adminitered to different sites in gastrointestianl tracts(stomach, small intestine and colon)of normal rats, the hypoglycemic effect was observed. RESULTS The hypoglycemic effect did not exist after intragastric administration of INS-PLA-NP whether or not DOC was added. The alleviatory hypoglycemic effect was evident after intraintestinal absorption of INS-PLA-NP. After DOC was added, the absorption of INS-PLA-NP was accelerated obviously and the hypoglycemic effect was strengthened significantly. Glucose levels hardly changed after INS-PLA-NP was administered to colon. With the use of DOC, a little hypoglycemic effect appeared. CONCLUSIONS The absorption of INS-PLA-NP in small intestine was accelerated and enhanced by DOC. DOC could be used as absorption enhancer of INS-NP in the future.