Neutropenia is a frequent complication of anticancer chemotherapy (CT) often associated with life-threatening infections, hospitalization, dose reduction and/or delay in the administration of CT. Administration of recombinant granulocyte colony-stimulating factor (rG-CSF) reduces the duration and the degree of CT-neutropenia. rG-CSF that stimulates both neutropoiesis and neutrophil function, has become an integral part of supportive care during cytotoxic CT, to prevent febrile neutropenia (FN), particularly in patients with a risk of FN ≥ 20%. International guidelines have standardized conditions for rG-CSF administration, however, some 'gray zones' still exist around optimal timing and tailoring of this therapy. We report here the results of a research project aimed to extend the consensus on the optimal use of rG-CSF in association with CT in patient with solid tumours. We also propose a recently developed pharmacodynamic model, based on the biological effects of CT and rG -CSF on bone marrow compartments that clearly indicates within the prophylactic rather than therapeutic setting the better way of rG-CSF administration.