Abstract: Disclosed is the use of Bifidobacterium and berberine in the preparation of a medicament for treating pre-diabetes or type 2 diabetes mellitus. Specifically, the medicament is applicable to pre-diabetic patients, or patients of type 2 diabetes mellitus with fasting plasma glucose (FPG) level being 5.6 mmol/L or more and lower than 8.0 mmol/L, or venous plasma glucose at 2 hours post OGTT being 7.8 mmol/L or more and less than 17 mmol/L.