Botulinum toxin is used for an increasing number of indications in the field of gastroenterology. We report a case in which injection of botulinum toxin in the dilated tubular oesophagus in a patient with achalasia was complicated by a pneumothorax necessitating suction drainage. EurJ Gastroenterol Hepatol 15:561-564 (C) 2003 Lippincott Williams Wilkins.