Sepsis, septic shock, acute bacterial meningitis, lobar pneumonia, infective endocarditis and necrotizing fasciitis are emergencies in infectology. The diagnosis is made on the basis of a quality anamnesis, complete physical examination and laboratory tests. The basics of treatment are antimicrobial and supportive therapy. Sepsis is defined as a life-threatening organ dysfunction obtained by an uncontrolled host response to infection. The symptoms and signs of sepsis are nonspecific. SOFA scoring helps in making the diagnosis. The foundations of sepsis treatment are ensuring hemodynamic stability and resolution of infection by antimicrobial therapy. Meningitis is an inflammation of the meninges, and is defined by an abnormal number of white blood cells in the cerebrospinal fluid. Meningeal signs and cerebrospinal fluid analysis play an important role in diagnosing meningitis. The basis of treatment are antimicrobial therapy, stoping the raising of intracranial pressure and the development of sepsis. Pneumonia is a clinical term that represents inflammation of the lung parenchyma. Radiological examinations are of special importance in the diagnosis of pneumonia. The pneumonia severity index is used to assess the severity of the disease. Infectious endocarditis is an infection of the inner layer of the heart. Symptoms and signs are nonspecific. Echocardiography is of great importance in proving infectious endocarditis. The Duke criteria are used to make a diagnosis. In addition to antimicrobial therapy, surgery may be required. Necrotizing fasciitis is a severe infection of the subcutaneous soft tissue and muscle fascia. The gold standard for diagnosis is a surgical exploration. Surgery and antimicrobial therapy are the main treatment for necrotizing fasciitis