CASE PRESENTATION: A 64-year-old female with IPF was diagnosed with stage IIIa cecal adenocarcinoma. Prior to the diagnosis of cancer, her IPF was characterized by stable dyspnea (MRC class 1-2), bibasilar and sub-pleural reticular opacities with traction bronchiectasis on CT scan, and mild lung volume restriction and moderate diffusion impairment on pulmonary function testing (PFT). The patient underwent right hemi-colectomy and received FOLFOX adjuvant chemotherapy. After six cycles of FOLFOX her dyspnea worsened dramatically (MRC Class 4). Further chemotherapy was suspended. PFT’s revealed a significant deterioration of her diffusing capacity and lung volumes. CT scan demonstrated air-bronchograms and traction bronchiectasis bilaterally. Bronchoscopy did not reveal evidence of infection, malignancy, or endobronchial pathology. Antimicrobials failed to provide relief. By process of exclusion, the deterioration was attributed to oxaliplatin. Subsequently her symptoms and PFT abnormalities returned to baseline. Open lung biopsy then demonstrated usual interstitial pneumonitis, consistent with the prior clinico-radiologic diagnosis of IPF.