Biological monitoring is a set of activities which can confirm the toxic effects of different substances present in the body, using the qualitative (cytological or histopathological) or quantitative methods (by determining the concentrations of different substances and their metabolites in biological media such as blood, urine, serum, specific tissues, etc.). In addition, biomonitoring can confirm or exclude the cytotoxic or genotoxic effect of various physical and chemical agents present in the body, especially in the conditions of its chronical exposure. It means that various chemical agents or pharmaceuticals as drugs administered into the body in increased concentrations for a long time may have toxic or carcinogenic effect. In the human biomonitoring, different specific bioindicators (markers) are used, which can confirm the presence of various chemical agents in the body and their effects on cells or molecules. The term "marker" means any substance or change in the cells or tissues that can be identified or measured. The most commonly used biological medium for human biomonitoring is blood. Project goals: This is a fundamental research that can be found in further clinical practice becaouse the project goal is biomonitoring of the cytotoxic effects of statins (chemical agents used in patients with dyslipidemia), as an effective therapy for lowering the concentration of cholesterol in the blood. Patients and methods: The study will include subjects, mainly patients of different ages, who are on therapy with statins for a long time. - Biochemical markers will be monitored, such as hepatic enzymes (serum transaminases) and other enzymes (such as creatine kinase) in correlation with the dose of statins; - Cytological biomarkers will be monitored to confirm the cytotoxic effect of statins on the cells; - We will compare the values of hepatic and other enzymes in the body with the dose of statins and others values as BMI, biochemical and hematological parameters that indicate certain pathophysiological changes in the organism (myalgia, hepatic changes, renal insufficiency etc.). Expected results: We expect that in the subjects who have been treated for a long time, statins will induce the following changes: - increased values of certain liver enzymes (such as serum transaminases) and other enzymes (creatine kinase) as important biochemical biomarkers for the cytotoxicity of these drugs; - cytological changes as important biomarkers that indicate cytotoxicity in the organism according to the duration and dose of statins; - the same changes will be correlated with other biochemical and genotoxicological biomarkers and others pathophysiological changes in the body.