ImportanceAlthough nasal suctioning is the most frequently used supportive management for bronchiolitis, its benefit remains unknown.ObjectiveTo evaluate the effectiveness of enhanced vs minimal nasal suctioning in treating infants with bronchiolitis after discharge from the emergency department (ED).Design, Setting, and ParticipantsThis single-blind, parallel-group, randomized clinical trial was conducted from March 6, 2020, to December 15, 2022, at 4 tertiary-care Canadian pediatric EDs. Participants included otherwise healthy infants aged 1 to 11 months with a diagnosis of bronchiolitis who were discharged home from the ED.InterventionsParticipants were randomized to minimal suctioning via bulb or enhanced suctioning via a battery-operated device before feeding for 72 hours.Main Outcomes and MeasuresThe primary outcome was additional resource use, a composite of unscheduled revisits for bronchiolitis or use of additional suctioning devices for feeding and/or breathing concerns. Secondary outcomes included health care utilization, feeding and sleeping adequacy, and satisfaction.ResultsOf 884 screened patients, 352 were excluded for criteria, 79 declined participation, 81 were otherwise excluded, 372 were randomized (185 to the minimal suction group and 187 to the enhanced suction group), and 367 (median [IQR] age, 4 [2-6] months; 221 boys [60.2%]) completed the trial (184 in the minimal suction and 183 in the enhanced suction group). Additional resource use occurred for 68 of 184 minimal suction participants (37.0%) vs 48 of 183 enhanced suction participants (26.2%) (absolute risk difference, 0.11; 95% CI, 0.01 to 0.20; P = .03). Unscheduled revisits occurred for 47 of 184 minimal suction participants (25.5%) vs 40 of 183 enhanced suction participants (21.9%) (absolute risk difference, 0.04; 95% CI, −0.05 to 0.12; P = .46). A total of 33 of 184 parents in the minimal suction group (17.9%) used additional suctioning devices vs 11 of 183 parents in the enhanced suction group (6.0%) (absolute risk difference, 0.12; 95% CI, 0.05 to 0.19; P < .001). No significant between-group differences were observed for all bronchiolitis revisits (absolute risk difference, 0.07; 95% CI, −0.02 to 0.16; P = .15), ED revisits (absolute risk difference, 0.04; 95% CI, −0.03 to 0.12; P = .30), parental care satisfaction (absolute risk difference, −0.02; 95% CI, −0.10 to 0.06; P = .70), and changes from baseline to 72 hours in normal feeding (difference in differences, 0.03; 95% CI, −0.10 to 0.17; P = .62), normal sleeping (difference in differences, 0.05; 95% CI, −0.08 to 0.18; P = .47), or normal parental sleeping (difference in differences, 0.10; 95% CI, −0.02 to 0.23; P = .09). Parents in the minimal suction group were less satisfied with the assigned device (62 of 184 [33.7%]) than parents in the enhanced suction group (145 of 183 [79.2%]) (risk difference, 0.45; 95% CI, 0.36 to 0.54; P < .001).Conclusions and RelevanceCompared with minimal suctioning, enhanced suctioning after ED discharge with bronchiolitis did not alter the disease course because there were no group differences in revisits or feeding and sleeping adequacy. Minimal suctioning resulted in higher use of nonassigned suctioning devices and lower parental satisfaction with the assigned device.Trial RegistrationClinicalTrials.gov Identifier: NCT03361371