Patients with Fontan palliation and single-ventricle physiology encounter multiple comorbidities including plastic bronchitis, a disease characterised by the plugging of small and large airways by rubbery, white casts. To date, no controlled clinical trials have demonstrated effective treatment of plastic bronchitis. We report the application of aerosolised heparin, which has published success in non-cardiac-related pulmonary disease, for this complication in a Fontan patient.