This textbook contains a systematic presentation of the course of biological chemistry according to the educational program for students of higher medical (pharmaceutical) educational establishments. The core text of this book examines the structure of an enzyme, and the metabolic pathways of the major classes of biomolecules (proteins, amino acids, carbohydrates, lipids, nucleotides, porphyrins); structural features and properties of nucleic acids, DNA and RNA; molecular biology and genetics, biochemical foundations of the physiological functions of the human body and their neurohumoral regulation are highlighted. Considerable attention is paid to the molecular mechanisms underlying the functions of blood cells, liver, kidneys, muscles, connective tissue, immune and nervous systems. The biochemical basis of the pathogenesis of atherosclerosis, diabetes mellitus, obesity, diseases of the endocrine, immune, nervous systems and connective tissue are considered. In addition to informational material, each chapter of the textbook contains tests and tasks for self-control.