Lactate dehydrogenase is a glycolytic enzyme found in the cytoplasm of all tissues and cells in the body, with the highest levels found in the kidneys, followed by cardiac and skeletal muscle. Clinical measurement of lactate dehydrogenase and its isoenzymes is commonly used in the diagnosis and differential diagnosis of diseases of the heart, liver, and skeletal muscle. Lactate dehydrogenase catalyzes the production of pyruvate from dehydrogenated lactate. Low lactate dehydrogenase is usually caused by endocrine disorders, overwork, poor sleep and bad mood. It is usually not very serious and can be recovered after life modification. If the lactate dehydrogenase is high in the examination, heart, liver and kidney diseases can be considered, which are commonly found in acute hepatitis, myocarditis, malignant tumors, cirrhosis of the liver, hepatocellular carcinoma, acute leukemia, pernicious anemia and other diseases. When lactate dehydrogenase fluctuates, it is recommended to consult a doctor in time and follow the doctor’s instructions for further examination and targeted treatment.