Haematological toxicity of chemotherapy is a very important problem in oncology. The introduction of granulocyte colony-stimulating factor (G-CSF) into clinical practice is one of the most important breakthrough moments in supportive care. The use of G-CSF allows to reduce the risk of febrile neutropenia and maintain the intensity of oncological treatment, so increases not only the safety, but also the effectiveness of cancer therapy. The application of biosimilars, including biosimilar filgrastim and pegfilgrastim, was another important step that made it possible to increase access to modern biological medicines.