Neither black tea nor cooked pu-erh has the effect of lowering blood sugar, and patients are advised not to listen to advertisements or prescriptions. If you want to control your blood sugar, you should use hypoglycemic drugs for treatment according to the advice of your healthcare provider. Common medications include insulin, metformin, and pioglitazone. Black tea and ripe pu-erh, as daily drinks, have some positive effects on health when consumed in moderation. However, they cannot cure diseases and lower blood sugar. If high blood sugar occurs, in addition to medication, scientific care is needed to maintain a low-fat, low-sugar and low-salt diet. If the blood sugar is high and the control is unsatisfactory, you should seek medical treatment in time and do not listen to prescriptions.