High hydroxybutyrate dehydrogenase after chemotherapy is considered to be related to myocardial injury caused by chemotherapy, and other indicators of myocardial enzyme profiles should be closely monitored and electrocardiograms should be performed. Chemotherapy is an important measure for the treatment of malignant tumors, and it also has a certain killing effect on normal myocardial cells, so it will lead to myocarditis in some patients. Mild asymptomatic myocardial injury, pay attention to rest will be gradually relieved, patients do not need to worry too much, if necessary, you can apply nutritive myocardial drugs. For patients with obvious symptoms such as chest tightness, shortness of breath, or electrocardiogram with signs of myocardial injury, it is necessary to stop chemotherapy drugs in a timely manner, active nutrition of the myocardium and other symptomatic treatment, to avoid serious injury. Therefore, mild elevation of hydroxybutyrate dehydrogenase after chemotherapy should pay attention to rest, and those with obvious clinical signs need to consult a doctor for timely treatment.