A blind randomized trial was conducted in a low-income community in the city of Recife, Pernambuco, Brazil, with 193 anemic (Hb<12mg/dl) and "menstruating" women (age range: 15-45 years) to compare daily and weekly doses of ferrous sulfate (60 mg elemental iron) and treatment compliance. Blood samples were taken from 484 women to determine hemoglobin levels before and after the trial and mean corpuscular volume (MCV) at end of treatment. After 12 weeks' follow-up, 150 women completed the trial, 79 on the alternative weekly regimen and 71 on the conventional daily regimen. Mean corpuscular hemoglobin concentrations (MCHC) prior to treatment were 10.52 g/dl (DP = 1.13) and 10.72 g/dl (DP = 0.92), respectively, for the alternative and conventional regimens. After the intervention they were 11.83 g/dl (DP = 0.97) for the weekly regimen and 11.62 g/dl (DP = 1.39) for the daily one. The alternative regimen was better accepted than the conventional one. There was no significant difference (p = 0.22) between differences in the mean values of the two regimens, although the cure rate was higher after the alternative treatment. The study concluded that the weekly regimen was no less effective than daily treatment.