Infection, hemorrhage and adult respiratory distress syndrome (ARDS) are pulmonary complications occurring after remission induction therapy for acute leukemia. The aim of this study was to analyze the incidence of these causes by serial roentgenogram, clinical, microbiological and laboratory tests in 21 patients (pts) with relapsed acute leukemia (18 X myeloid, 3 X lymphoblastic), an AML-pt (acute myeloid leukemia) suffering from secondary leukemia, and three pts with primary refractory leukemia following treatment with intermediate (IM) and high-dose cytosine arabinoside (HD-Ara C), in combination with amsacrine (AMSA)(n = 19), etoposide (VP 16) (n = 5) or Mitoxantrone (n = 1). Eleven out of 25 pts developed pulmonary complications, one of them with massive hemoptysis and roentgenographic signs of pulmonary bleeding, one suffering from protracted shock after a tumor lysis syndrome, two pts showing symptoms of a cardiogenic pulmonary edema complicating severe Candida pneumonia in one case and legionnaires' disease in the other. Seven of the eleven pts had a non-cardiogenic pulmonary edema with respiratory failure 1-14 days after cessation of induction or consolidation therapy. In six of the seven, there were no signs of cardiogenic, infectious or metabolic reasons, including fluid overload, for the pulmonary edema, one had as a contributing factor a Candida infection of the lung. Three of the seven patients recovered, four died (two following IM and two after HD-Ara C). Other adverse side effects, clearly attributable to HD-Ara C, included delirious state (n = 3), generalized erythema (n = 3), acute pancreatitis (n = 2), acute abdomen (n = 1) and conjunctivitis in almost all patients.(ABSTRACT TRUNCATED AT 250 WORDS)