The article is dedicated to the most relevant issue of childhood – febricities, the causes of which and, subsequently, correct patient management tactics are difficult to determine. The authors present not only their own experience of clinical and laboratory differential diagnostics of viral and bacterial infections, but also the world literature data. Low bacterial infection risk criteria, which allow avoiding the prescription of antibacterial drugs, are listed. Special attention is given to the most important inflammation markers at various febrile diseases and signs of a severe bacterial infection and fever without an apparent infection’s nidus. The authors recommend using express tests to confirm the presence of a bacterial infection. Indications to antibacterial therapy prescription are analyzed.