Inclusion Criteria:  18-70 years old; education level higher than middle school; met the Rome IV criteria for FD; absence of abnormalities on physical examination, laboratory tests (including a routine blood test, blood glucose, and liver function examination), and abdominal imaging and GI endoscopy within 6 months; absence of Helicobacter pylori infection; signed written informed consent for participation in the study.  Exclusion Criteria:  evidence of organic digestive diseases; diabetes, cancer and other diseases might affect GI function; pregnancy, lactation or breastfeeding; a history of allergic reaction to any of the drugs used in the study; participation in other clinical trials in the previous 3 months.