Berberine (BBR) is the main active ingredient of the ancient Chinese herb medicine Coptis. The hypoglycemic effect of BBR has been demonstrated in numerous studies. Although BBR is safe and effective in the treatment of diabetes, its exact hypoglycemic mechanism is still unclear. Jin-Kui Yang found that BBR can promote GLP-1 secretion from intestinal L cells in mice in vitro and in vivo, thereby achieving the effect of lowering blood glucose, but it is still unknown whether BBR can promote incretin secretion in humans. In this study, investigators plan to examine the effect of BBR on secretion of incretin in human.

Inclusion Criteria:

1. Voluntary participation in the trial and signed informed consent form.
2. Healthy male subjects aged 18-45 years (including 18 and 45 years).
3. No history of current or former diseases such as heart, liver, kidney, gastrointestinal tract, nervous system, respiratory system, mental disorders and metabolic abnormalities that the investigator considers meaningful; no physical examination, electrocardiogram, and laboratory examination results abnormality or abnormality has no clinical significance (subject to the judgment of the physician).
4. Body mass index of 18.0-25.0 kg/cm2 (including 18.0 and 25.0 kg/cm2) and no centripetal obesity (waist-to-hip ratio less than 0.9).
5. No family history of diabetes mellitus and obesity.
6. Normal glucose tolerance (fasting blood glucose <6.1 mmol/L and 2h blood glucose <7.8mmol/L after oral administration of 75g glucose) and normal insulin secretion function (as judged by the investigator through the results of insulin release experiment).
7. Able to communicate well with the investigator and complete the study in accordance with the study regulations.

Exclusion Criteria:

1. Infection with hepatitis (A, B, or C), HIV and syphilis.
2. Those with clear allergy to berberine hydrochloride or its preparation components; those with drug (including salicylic acid) allergy, history of allergic diseases or allergic constitution.
3. Patients with hemolytic anemia and glucose-6-phosphate dehydrogenase deficiency.
4. Those who have used any prescription medication, herbal medicine within 4 weeks prior to dosing and/or taken over-the-counter medication (except for subjects with occasional or restricted use of paracetamol), supplements (except for routine vitamin supplementation) within 2 weeks prior to dosing.
5. Cumulative amount of blood loss (eg. blood donation) over 400mL within 3 months prior to baseline visit and during the study.
6. Heavy smokers (25 or more cigarettes per day) and heavy drinkers (14 units of alcohol per week, 1 unit = 285ml of beer, or 25ml of spirits, or 100ml of wine).
7. Those with a history of substance abuse or positive urine test for prohibited drugs.
8. Those who participated in any clinical trial within 1 month prior to the trial, or those who plan to participate in other clinical trials during or within 1 month after the end of the trial.
9. Other circumstances that the investigator considers unsuitable for participation in this study.