Headache after dialysis is mainly considered to be caused by too much dialysis water, dialysis imbalance and high blood pressure. 1. Excessive dialysis water: too much and too fast dehydration in dialysis, insufficient blood volume in the body and impaired blood supply to the brain may lead to dizziness, headache and other symptoms. 2. Imbalance of dialysis: after dialysis, more toxins are removed from the blood, because of the existence of blood-brain barrier, the toxins in the brain are relatively high, which may lead to cerebral edema and then headache after dialysis. 3. Hypertension: During the process of dialysis, blood pressure may be elevated. High blood pressure may cause headache. Headache after dialysis should be examined in a timely manner to clarify the cause of the disease and be treated under the guidance of specialized physicians.