BACKGROUND: Chemotherapy with oxaliplatin and 5-fluorouracil (5-FU)/folinic acid is the standard first-line therapy of metastatic colorectal carcinoma and has shown activity in several other malignancies. This regimen is mostly well tolerated. Known side effects include myelosuppression, nausea/vomiting and neuropathies; acute pulmonary toxicity has only been described in very few reports. CASE REPORT: A 66-year-old male with metastatic rectal adenocarcinoma treated with 12 cycles of oxaliplatin and 5-FU/folinic acid developed bilateral pulmonary infiltrates and respiratory failure. Broad-spectrum antibiotic therapy did not improve his condition and extended microbiological diagnostics did not show an infectious etiology. Therapy with corticosteroids led to a short improvement, however the patient died 1 week after the initiation of corticosteroid treatment due to respiratory insufficiency. The clinical and histopathological data as well as the lack of an infectious cause indicate that pulmonary fibrosis was induced by oxaliplatin and 5-FU/folinic acid. CONCLUSION: This case demonstrates that treatment with oxaliplatin and 5-FU/folinic acid can cause acute pulmonary fibrosis. Even though pulmonary toxicity is rare in patients treated with this chemotherapy regimen compared to infectious pulmonary complications, it should be considered early in the clinical course of otherwise unexplained pulmonary infiltrates hopefully leading to a better outcome. (c) 2008 S. Karger AG, Basel