Lactate dehydrogenase is a glycolytic enzyme that is present in the cytoplasm of all tissues and cells in the body, with the kidney being the most abundant. There are three reasons for elevated lactate dehydrogenase: First, liver function damage, different causes of liver function damage may cause elevated values of lactate dehydrogenase, the need to apply liver-protecting and enzyme-lowering drugs for treatment, of course, it depends on the specific value. If the kidney is damaged by improper consumption of drugs, the lactate dehydrogenase value may also be elevated, which requires symptomatic treatment. If there is no increase in creatinine and urea nitrogen, the effect on the child is not particularly large. The most common cause of elevated lactate dehydrogenase in children is myocardial injury, which needs to be treated with drugs that nourish the heart muscle. In addition to the cardiac enzyme test, an electrocardiogram and cardiac ultrasound should be performed. If myocarditis is diagnosed, the treatment should take longer, at least 10-14 days.