Blood expectoration or hemoptysis is the coughing up of sputum with blood from the larynx, bronchi or lungs. Hemoptysis is most often caused by diseases of the respiratory tract and lungs — bronchitis or pneumonia, as well as lung cancer, aspergilloma, tuberculosis, bronchiectasis, pulmonary embolism, etc. In the diagnostic investigation of the cause of hemoptysis, it is important to take a detailed history (in the case of an epidemiological history, a laboratory analysis of the secreted sputum for the detection of the causative agent of an infectious disease is necessary), to make the correct interpretation of the patient’s complaints and an assessment of the nature of the sputum (differential diagnosis with bleeding from the upper gastrointestinal tract). A chest X-ray is performed and, then, if indicated, computed tomography, bronchoscopy, and other studies are made. The article presents an algorithm for differential diagnostic investigation of hemoptysis in a patient