How long it takes for a high homocysteine level of 45umol/L to come down varies from person to person and is mainly related to the patient’s treatment and individual factors, and cannot be generalized. If a patient’s blood homocysteine level is greater than 10umol/L, and if no active measures are taken, homocysteine values can remain high for a long time and can cause significant cardiovascular and cerebrovascular harm. If patients take timely supplements such as folic acid and vitamin B6 and vitamin B12, homocysteine values can generally drop in about 3 weeks, but the exact time cannot be specified. In addition, patients should pay attention to eating less fatty meat, cheese and other high-protein foods in daily life, quit smoking and drinking alcohol, and refrain from drinking coffee and strong tea. At the same time, keep emotional stability, do not stay up late, etc. Patients can also maintain a stable homocysteine value by eating more green leafy vegetables, exercising and other healthy lifestyles.