Aim. To extend criteria of ACS severity and prognosis based on phospholipids level and blood aqueous component state and to evaluate mexidol's effectiveness in complex of standard therapy. Material and methods. Study included 120 patients with ACS followed by unstable angina in 39 cases (group 1), non-Q-wave myocardial infarction - 19 (group 2) and Q-wave myocardial infarction - 62 patients (group 3). Mexidol was not applied in 30 patients (subgroup A) and was administered in 30 cases (subgroup B). Functional parameters, blood aqueous component state and percentage absorption of lipid-phospholipid complexes in infrared spectrum of blood serum in 9 channels were studied before and during intravenous injection of mexidol 250 mg for 10 days depending on clinical form of ACS. The control group consisted of 20 healthy people. Results. For the first time it was found that dynamics of lipid-phospholipid complexes and blood serum aqueous component are associated with degree of myocardial injury. Mexidol is myocardial cytoprotector that increases myocardial tolerance to ischemia and reduces necrosis area. Conclusion. Indicators of aqueous component, phosphorus and atherogenic serum lipids are prognostically significant due to their correlation with ACS. Mexidol's positive impact on phospholipids level and cardiodynamics justifies its inclusion into complex therapy of ACS.