Filgrastim is a medication used to stimulate the production of white blood cells in the body. It belongs to a class of drugs known as granulocyte colony-stimulating factors (G-CSFs).

White blood cells, also known as leukocytes, are a crucial part of the immune system responsible for fighting off infections and other foreign invaders. In some situations, such as cancer chemotherapy or bone marrow transplantation, the body’s production of white blood cells may be suppressed, leading to an increased risk of infections.