The textbook was prepared in accordance with the curriculum on military toxicology, radiology and medical protection for cadets of military medical educational institutions and students studying in the specialties of higher professional education of the Healthcare group with the development of the military training program. It sets out the goals, objectives, structure, basic concepts and terms of toxicology and radiobiology, general patterns of interaction of the human body with chemicals and ionizing radiation, the main forms of toxic processes and radiation lesions. The classification of toxic and highly toxic substances that can cause damage to people under extreme influences is given, the mechanism of their action, pathogenesis and clinical manifestations of intoxication, the principles of diagnosis and treatment of acute poisoning are described.