Plastic bronchitis is a rare and potentially fatal disease. Mainly a disease of the pediatric age, a few adult cases occurring after cardiac surgery have been described. We describe a case of a 41-year-old man suffering from several episodes of acute dyspnea and cough with expectoration of mucous plugs in the context of chronic allergic airway inflammation. We believe that the occurrence of plastic bronchitis in adulthood should not be overlooked particularly in patients with chronic inflammatory lung disease.