A 54-year-old female presented with a 2-week history of increasing shortness of breath and fever. She had a history of a poorly differentiated sigmoid adenocarcinoma for which she underwent an anterior resection 6 months prior to admission, followed by 12 cycles of adjuvant FOLFOX chemotherapy. The patient was treated for a severe community-acquired pneumonia; however, she remained hypoxic. A chest CT revealed extensive right-sided fibrotic changes, tractional dilatation of the airways and ground glass density, which had developed since a staging CT scan performed 2 months previously. Although her symptoms improved with steroid therapy, repeat imaging revealed that right hydropneumothorax had developed, and this required the insertion of a chest drain. Following its successful removal, the patient continues to improve clinically and radiographically. The rapid onset and nature of these changes is consistent with a drug-induced fibrotic lung disease secondary to FOLFOX chemotherapy. The phenomenon is underreported and yet, it is relatively common: it occurs in approximately 10% of patients who are treated with antineoplastic agents, although information specifically relating to FOLFOX-induced pulmonary toxicity is limited. It is associated with significant morbidity and mortality, but is often hard to differentiate from other lung conditions, making the diagnosis a challenge. Pulmonary toxicity is an important complication associated with antineoplastic agents. It should be considered in any patient on a chemotherapeutic regimen who presents with dyspnoea and hypoxia in order to try to reduce the associated morbidity and mortality.