An increased incidence of severe infections, in particular gastrointestinal complications, was observed in our institution among 35 consecutive patients with acute myelogenous leukemia submitted to their first intensive pilot protocol for induction of remission containing idarubicin, etoposide and cytosine arabinoside. Ten patients presented fever and severe diarrhea (4 or more loose stools/day for at least 4 consecutive days); 3 of these developed ileothyphlitis, which proved fatal in 2 cases, 7 needed amphotericin B addition to antibacterial treatment and, in 6 cases, a fungal infection was documented. We have compared these 10 patients with the other 25 submitted to the same chemotherapeutic protocol and the incidence of candidemias (5/10 compared to 0/25), the early use of systemic fluconazole from the onset of fever (0/10 compared to 9/25) and the pre-emptive use of total parenteral nutrition (0/10 compared to 8/25) differed in the two groups. We conclude that during this chemotherapeutic protocol the incidence of severe gastrointestinal infectious complications was particularly high (28.5%) and, even though only a small number of patients were studied, our results suggest an important role for Candida spp. in the pathogenesis of this disease.