Blood donation generally does not improve blood viscosity. 1. Blood viscosity is also known as increased viscosity of the blood, and blood viscosity is related to many factors, such as overweight, oily diet, long-term alcoholism and smoking, less exercise, or a combination of hypertension, diabetes mellitus, hyperlipidemia, chronic myeloproliferative neoplasms and other diseases. 2. If you want to improve blood viscosity, you can drink more water, eat more fresh fruits and vegetables, strengthen exercise, kong diet, etc., to improve the metabolic function of the body, so as to improve or prevent the situation of increased blood viscosity. 3. In addition, if you are suffering from some underlying diseases, such as hypertension, diabetes mellitus, hyperlipidemia, chronic myeloproliferative neoplasms, etc., you need to make adjustments through some medications to lower the blood lipids so that the blood lipids are within the normal range. So by donating blood, the improvement of blood viscosity generally cannot be achieved. If you find blood viscosity, you should go to regular hospitals for timely and symptomatic treatment, so as not to affect your health and delay your condition.