Résumé : Background: Pharmacists have an important role to play in detecting and resolving drug-related problems (DRPs). Most studies have shown that DRPs have a negative impact on clinical results and quality of life as well as on health care costs. Corticosteroids are often implicated in DRPs, in particular because of their side effects, incorrect use of the inhalation device or lack of adherence to the prescribed regimen.Purpose: The purpose of this work is to identify causes of DRPs and interventions performed by pharmacists on corticosteroid-related problems and to distinguish between problems related to inhaled and general corticosteroids.Methods: During 5 days of their internship, 530 final year students of pharmaceutical sciences in six Belgian universities collected DRPs encountered in community pharmacies, as well as related interventions performed by pharmacists. The DRPs’ electronic registration was done through an adapted tool based on the classification of Pharmaceutical Care Network Europe (PCNE - v 6.2). This tool was validated by pharmacists and allowed to measure the frequency and nature of DRPs.Findings: Pharmacists detected 16 733 DRPs in total. 555 DRPs (3.3%) related to corticosteroids, of which 115 were inhaled corticosteroids. The most common causes of corticosteroid-related problems (55%) were administrative and logistical factors and fraud. More than a half of the technical causes were incomplete prescriptions. Concerning clinical causes, 28% related to drug/device-use problems for inhaled corticosteroids, with 88% related to incorrect use of the inhalation device. For general corticosteroids, the most common clinical causes were drug choice (37%), including medication interaction (58%) and inappropriate medication (contraindications, side effects: 14%). Pharmacists’ intervention was similar for inhaled and general corticosteroids. Pharmacists intervened with the patient orally in 38% of total interventions, and in writing in more than 14% of interventions. Pharmacists did not react in 14% (inhaled corticosteroids) and 16% (general corticosteroids) of corticosteroid-related problems. These non-interventions covered, for example, interactions and incomplete prescriptions.Conclusion: Several corticosteroid-related problems were detected and solved. However, pharmacists barely intervened for non-observance and drug interactions. The introduction of a structured interview between the patient and the pharmacist would enable the patient to be educated and informed about his disease and treatment. Therefore, pharmacists’ training is essential to performing these interviews. More randomized studies should be done in community pharmacies to evaluate the impact of these interviews on patients and on therapeutic adherence in real time.