Fasting blood sugar means not eating carbohydrates, or drinks containing calories, for at least eight hours in the early morning, so you can drink water normally before measuring fasting blood sugar, and cannot eat. Whether you can take medicine before measuring fasting blood glucose needs to be distinguished according to the type of medicine, and there are the following cases: 1. If a diabetic patient takes oral hypoglycemic drugs, you cannot take hypoglycemic drugs before measuring fasting blood glucose, because the time between hypoglycemic drugs and meals is fixed. If you simply take the medicine without eating normally it will lead to low blood sugar, and in serious cases, hypoglycemia or even hypoglycemic coma will occur. If postprandial blood glucose is measured, it should be measured under normal eating and normal taking of medication.2. Drugs other than oral hypoglycemic drugs, such as blood pressure, coronary heart disease drugs, etc., can be taken normally before measuring fasting blood glucose, which does not affect the results of blood glucose measurement.