To assess the role of Candida spp. in the etiology of neutropenic enterocolitis complicating aggressive cytotoxic chemotherapy, a dot immunobinding assay for an immunodominant Candida mannoprotein antigen was employed in 20 patients with hematologic malignancies. Candida antigen was detected in at least one serum sample from 12 (60%) patients. Eleven (92%) patients were cured when an antifungal agent was added to the antibacterial treatment. In eight patients a selective anticandidal therapy with fluconazole was administered on the basis of positive Candida mannoproteinemia, and treatment was successful in all cases but one. Detection of Candida mannoproteinemia seems to be a useful diagnostic tool in patients with neutropenic enterocolitis and represents an additional tool for selecting a less empiric, low toxic antifungal treatment with fluconazole.