Low homocysteine has no special clinical significance and is a normal physiological phenomenon because homocysteine can be broken down in the body and is generally maintained at a low level. Homocysteine, also known as blood homocysteine, is a sulfur-containing amino acid, an important intermediate product produced by methionine and cysteine in normal metabolism. Blood homocysteine can be broken down in the body, and the level is generally maintained at a low level, which does not have a great impact on the human body. If it is particularly low, it may be malnutrition, and the specifics of which should be consulted with the doctor. The normal value of blood homocysteine is 5~15μmol/L, low level has little effect on the body, what should be alerted is the elevation of blood homocysteine, when elevated, the possibility of venous thrombosis will increase, will increase the risk of coronary heart disease as well as other cardiovascular and cerebral vascular diseases, when found that homocysteine is abnormally elevated, should be promptly consult a doctor.