Background: There are no medications known that improve the outcome of infants with bronchiolitis. Studies have shown the management of bronchiolitis to be varied. Objectives: To describe medication use at the seven study hospitals from a recent multi-centre randomised controlled trial on hydration in bronchiolitis (comparative rehydration in bronchiolitis [CRIB]). Methods: A retrospective analysis of extant data of infants between 2 months (corrected for prematurity) and 12 months of age admitted with bronchiolitis identified through the CRIB trial. CRIB study records, medical records, pathology and radiology databases were used to collect data using a standardised form and entered in a single site database. Medications investigated included salbutamol, adrenaline, steroids, ipratropium bromide, normal saline, hypertonic saline, steroids and antibiotics. Results: There were 3456 infants available for analysis, of which 42.0% received at least one medication during hospitalisation. Medication use varied by site between 27.0 and 48.7%. The most frequently used medication was salbutamol (25.5%). Medication use in general, and salbutamol use in particular, increased by 8.2 and 9.3%, respectively, per month after 4 months of age; from 22.9 and 3.6% at 4 months to 81.4 and 68.8% at 11 months. In infants admitted to the intensive care unit (ICU) compared with those not admitted to ICU 81.6 and 39.5%, respectively, received medication at one point during the hospital stay. Conclusions: Medication was used for infants with bronchiolitis frequently and variably in Australia and New Zealand. Medication use increased with age. Better strategies for translating evidence into practice are needed.