To report two children admitted to our emergency department with respiratory failure, one for status asthmaticus with pneumomediastinum and requiring mechanical ventilation and the other for high suspicion of foreign body aspiration.

Bronchoscopy revealed obstructive plugs and permitted their extraction and their identification as bronchial casts after the immersion in normal saline. Allergy was suspected in the first one, and Hemophilus influenzae infection was present in the second. The outcome was favorable.

Plastic bronchitis is an infrequent cause of acute life-threatening respiratory failure that can mimic foreign body aspiration or status asthmaticus. Bronchoscopic extraction must be performed urgently in the case of severe obstruction. This entity is probably underestimated as the casts with their specific ramifications are difficult to recognize. We recommend the immersion in normal saline of all plugs discovered in children with predisposing diseases mainly represented by infections, allergy, acute chest syndrome, and congenital cardiopathies.