High D-dimer is caused by the following reasons: Firstly, cerebral infarction is prone to high D-dimer, and the embolism in the body can be judged by the high value of the aggregates. Secondly, it may be caused by platelet aggregation in the body, which is prone to the formation of blood clots if not treated in time, and may be accompanied by cough or shortness of breath, which can be treated with oral aspirin enteric tablets under the guidance of a doctor. In addition, it may also be caused by pulmonary embolism or lower limb vein embolism, and the location of the specific embolism can be clarified through imaging in a timely manner; in addition to the above-mentioned causes, tumor diseases cannot be ruled out, and if high D-dimer occurs, the cause must be identified in a timely manner and then treated symptomatically to avoid missing the best time to treat the disease.