Male db/db mice were purchased from Gene&Peace biotech Co., Ltd (Guangzhou, China). Mice were either used as control (Cont group, n=7) or orally gavaged with 0.25 g/kg chlorogenic acid (CA group, n=7) once a day. The experiment lasted 60 days and all animal had free access to water and feed. Then, blood were collected and mice were further treated by cervical dislocation to collect samples.