Background Although bronchoscopy can be part of the exploration of severe asthma in children, the benefit of bronchoalveolar lavage (BAL) is unknown. The present study aimed to decipher whether systematic BAL during a flexible bronchoscopy procedure could better specify the characteristics of severe asthma and improve asthma management. Material and methods The study took place in two departments of a university hospital in Paris. Children who underwent flexible bronchoscopy for the exploration of severe asthma between April 2017 and September 2019 were retrospectively included. Results In total, 203 children were included, among whom 107 had a BAL. BAL cell count was normal in most cases, with an increasing number of eosinophils with age, independently from the atopic status of the patients. Compared with bronchial aspiration only, BAL increased the rate of identified bacterial infection by 1.5. Nonatopic patients had more bacterial infections (p<0.001). BAL induced a therapeutic modification only for azithromycin and omalizumab prescriptions. The practice of a BAL decreased bronchoscopy tolerance (p=0.037), especially in the presence of tracheobronchial malacia (p<0.01) and when performed in a symptomatic patient (p=0.019). Discussion and conclusion Although BAL may provide interesting information in characterising severe asthma, in most cases its impact on the patient's management remains limited. Moreover, BAL can be poorly tolerated and should be avoided in the case of tracheobronchial malacia or current asthma symptoms.