High homocysteine is mainly related to genetic factors, nutritional and dietary factors, diseases and drug factors. 1. Genetic factors: Studies have found that there are polymorphisms in the methylenetetrahydrofolate reductase gene, with as many as 10 or so mutation sites, such as the common mutations at the A1298C site, C677T site, etc. These mutations can reduce the enzyme’s activity, affecting the activation of folic acid and leading to elevated homocysteine levels. 2. Nutritional and dietary factors: Insufficient intake due to pregnancy or other factors affecting gastrointestinal function, especially insufficient intake of vitamin 6, B12 and folic acid, can directly lead to abnormal metabolism of homocysteine, resulting in elevated homocysteine levels. Unhealthy dietary habits, such as alcohol consumption, can also cause elevated plasma homocysteine concentrations. 3. Disease and drug factors: renal failure, hypothyroidism, severe anemia, severe scleroderma, malignant tumors and other diseases, as well as the application of methotrexate, nitric oxide, nicotinic acid and other drugs, can lead to increased plasma homocysteine levels. When high homocysteine occurs, you should go to a regular hospital in time to clarify the cause of the disease and follow the doctor’s instructions for treatment.