A wide variety of noncytotoxic drugs, including antibiotics, analgesics, narcotics, and psychotrophic and cardiovascular agents, may cause lung injury accompanied by roentgenographic infiltrates. The clinical manifestations of drug-induced lung disease are protean. Patients may present with acute injury resembling the adult respiratory distress syndrome, which must initially be distinguished from bacterial sepsis. Other drug-associated lung injury is characterized by a more subacute pneumonitis similar to an atypical infectious pneumonia. Finally, some drugs may cause insidiously progressive pulmonary infiltrates that share features with granulomatous infections. The more common drug reactions are discussed in this review, and, although the features of drug-induced lung disease are often relatively nonspecific, those features that either mimic infectious causes or may be helpful in differentiating these processes from infections are given particular emphasis.