Drinking coffee usually can not lower blood sugar, coffee does not have the effect of lowering sugar. The main ingredient in coffee is caffeine, which has the effects of refreshing and diuretic, but there is no research showing that coffee has the function of lowering blood sugar. If diabetic patients want to drink coffee, it is recommended to choose black coffee, which is relatively low in sugar content and calories. Coffee also has certain side effects, such as insomnia, headache, palpitations, nausea and gastrointestinal discomfort. It is not recommended to drink a lot of coffee if you have coronary heart disease, high blood pressure, chronic gastrointestinal diseases or when you are in pregnancy. It is recommended that diabetic patients seek timely medical treatment and receive regular hypoglycemic treatment, including hypoglycemic drug treatment based on diet and exercise control, and do not believe in traditional Chinese medicine.