We evaluated the risk of neutropenia (defined using receipt of granulocyte colony-stimulating factor (G-CSF) prescriptions) under docetaxel administration or the coadministration of docetaxel and an interacting anticancer drug (predefined based on approval information obtained from the Korean Ministry of Food and Drug Safety and the Lexicomp electronic database). The gene discussed is CSF3; the disease is Decreased total neutrophil count.