ObjectiveTo retrospectively analyze off-label drug use (OLDU) situation of ambroxol hydrochloride injection (AHI) among inpatients in the Guangdong General Hospital in 2012, so as to provide references for AHI OLDU. MethodsAll medical orders of AHI for inpatients in the Guangdong General Hospital in 2012 were included, and OLDU was judged according to drug labels. We summarized situation of drug use in all departments, analyzed OLDU incidence in administration path and in dose, calculated prescribed daily dose (PDD) and utilization index (DUI) in each department to evaluate the degree of OLDU in dose. Resultsa) A total of inpatients 138 227 patient-days who used AHI were included. OLDU occurred in all departments in this hospital and the total OLDU incidence was 67.06%. b) OLDU in dose occurred in 71.43% of the departments (25/35) with an incidence of 29.53%; the top 4 departments were cardiac surgery intensive care unit department (CICU) (97.74%), cardiac surgery department (97.51%), pediatric cardiac surgery department (72.30%) and pediatric intensive care unit department (PICU) (70.28%) in order. c) The PDDs in CICU department, cardiac surgery department, PICU departments, pediatric cardiac surgery department, oncological surgery ward, neurosurgery ward and intensive care unit (ICU) were higher than the defined daily dose (DDD), of which, the DUI/cDUI in CICU, cardiac surgery department, PICU and pediatric cardiac surgery department were 1 to 3 times higher than normal level. d) No relevant adverse drug reaction/adverse event (ADR/AE) reports were received in this hospital in 2012. ConclusionAHI is widely used in the Guangdong General Hospital, and AHI OLDU is commonly-seen. Further studies should be conducted to analyze the influence factors of AHI OLDU in dose and to evaluate the rationality of its application.