The study included 238 cases of surgical treatment of patients with infectious endocarditis of left parts of heart. The operations of single or multivalve reconstruction or restoration in conditions of artificial circulation were made to these patients. The patients were divided into groups depending on the type of cardioplegic solution. The influence of methods of cold crystalloid (extracellu-lar and intracellular), and blood cardioplegia on clinical and laboratory indices, which characterize the severity of myocardial damage in intra - and postoperative periods, was studied. The obtained results showed that the use of all types of cardioplegic solutions allows to provide the myocardial protection during the operation and to decrease the risk of life-threatening complications in this category of patients. The increase in the level of laboratory parameters of myocardial damage was registered in the use of all types of cardioplegic solutions in patients with long anoxia. The lowest intensity of changes in the levels of blood lactate marked using a solution for cold crystalloid intracellular cardioplegia. The greatest changes of this indicator were identified in patients receiving blood potassium cardioplegia. The use of cardioplegic solution "Custodial" caused the greatest intensity of acidosis in the intra-operative period.