Drug-induced acute lung diseases constitute a chapter of pneumology and intensive care that is now in full mutation. In practice, these diseases are still inadequately indexed and little known, the only exception being those caused by cytotoxic drugs observed in onco-haematology. They create for clinicians difficult diagnostic and therapeutic problems. From the cases reported in the literature, recent review papers and 10 personal cases, the authors ask five successive questions concerning hypoxic pneumopathies: 1) which patients?; 2) which clinical features?; 3) which initial diagnostic discussion?; 4) which are the elements likely to support the drug-induced hypothesis?; 5) which outcome?