Due to the growing technology and the improvement of living standards with the unprecedented material abundance, cardiovascular disease has gradually become an invisible killer of health and longevity, however, people’s awareness of cardiovascular disease has to be improved, so I am sorry to be a teacher and promote the alternative causes of “ischemic cerebrovascular disease” to all of you. The term “ischemic cerebrovascular disease” is equivalent to “stroke” in Chinese medicine, and the causes of “ischemic cerebrovascular disease” are numerous and complex. The relationship between plasma homocysteine (hereafter referred to as cy) and cerebrovascular disease has been intensified, and it has been found that deficiency of vitamin B12 and folic acid can lead to ischemic cerebrovascular disease (i.e., hyperhomocysteinemia). Hyperhomocysteinemia is defined as an increase in free and protein-bound homocysteine and mixed sulfides in plasma or serum. Normal fasting plasma cy levels range from 5 to 15 mol/L, but levels above this range are called hyperhomocysteinemia. As the metabolism of cy and its role are better understood, the pathogenic role of cy in cerebrovascular disease is becoming increasingly important. There is a real need to understand the relationship between hyperhomocysteinemia and acute ischemic cerebrovascular disease. The relationship between cy and cerebrovascular disease was discovered and studied in foreign countries from the 1970s, and in the early 1990s, through large-scale clinical observations, it was initially determined that gender, age, race, lifestyle habits, disease, and other factors affect the level of blood cy and more frequent cardiovascular and cerebrovascular disease. In China, a large-scale study was carried out in the late 1990s. Since the north is a high incidence of cerebrovascular disease and the dietary habits of the resident population, the study of the relationship between cy, vitamin B12 and folate levels and cerebrovascular disease has been an important topic in the etiological study of cerebrovascular disease. Blood cy is a sulfur-containing amino acid, which is mainly generated by demethylation of methionine in liver, muscle and some other tissues, and is an important intermediate product in methionine metabolism in the body. Recent studies have found that the mechanism of vascular disease caused by hypercythemia is the increased generation of peroxides and oxygen radicals in the process of cy metabolism, which destroys the morphology of endothelial cells, causes endothelial cell dysfunction, disrupts the coagulation and anticoagulation function of endothelial cells, and promotes the proliferation of vascular smooth muscle cells, enhances platelet activity, increases their aggregation, increases fibrinogen production, and changes the coagulation status of blood, leading to vascular disease. This leads to the development of vascular diseases. In addition, studies have also found that blood cy has a common effect with hypertension, diabetes and hyperlipidemia, which can contribute to the development of vascular disease. Studies have shown that cy (homocysteinemia) is negatively correlated with folic acid and vitamin B12 deficiency, and that the causes of hypercythemia in the population can include nutrient deficiencies and genetic mutations causing enzyme deficiencies. Many papers have reported that hypercythemia is a new and independent risk factor for many diseases such as cardiovascular and cerebrovascular diseases, and some animal experiments have shown that hypercythemia can cause thrombosis, atherosclerosis-like pathological changes, and even neonatal malformations Note: For this reason, it is recommended that vitamin B12 and folic acid be taken once a day at any age, especially for pregnant women and the elderly, to benefit health.