Absorption of a physiological dose of ferrous iron was studied in 18 patients with solid malignancy receiving epoetin therapy for mild chemotherapy-associated anemia. The historical control group consisted of 25 iron replete volunteers (iron absorption 20 +/- 11% in males and 26 +/- 13% in females) and 21 patients with uncomplicated iron deficiency (iron absorption 71 +/- 19%). Iron absorption was increased in the majority of the cancer patients (iron absorption 59 +/- 35%). There were no significant differences in iron absorption between cancer patients who were iron replete or iron deficient according to current clinical practice guidelines (iron deficiency: transferrin saturation < 20% and/or serum ferritin < 100 ng/mL). Red cell iron incorporation was not disturbed in the majority (89%) of patients.