Neutrophilia (neutrophilia, neutrophilic leukocytosis) is an increase in the content of neutrophils over 6500 (in a child under 6 years old over 4500) in 1 μl of blood. The cause is bacterial infections, purulent-septic processes, inflammatory, oncological diseases. There are no specific clinical signs in neutrophilia, the symptoms depend on the underlying pathology. The level of neutrophils is determined as part of the calculation of the leukocyte hemogram formula. To correct neutrophilia, the disease against which it developed is treated.