This is a case of a 57-year-old gentleman with a history of chronic obstructive pulmonary disease (COPD) who presented with diarrhoea of more than 4 weeks in length. On chest x-ray, he was incidentally found to have a large cavitating lesion in his right lung. He denied having any respiratory distress at any stage and clinically he had been completely asymptomatic. The CT-guided biopsy confirmed a methicillin-resistant Staphylococcus aureus positive lung cavitation, most likely secondary to his poor dentition. A full dental clearance was performed, and he was treated with a course of intravenous vancomycin and oral clindamycin with good effect.