The median increase in Hb levels was similar in mild anemia, whereas in moderate-to-severe anemia, patients receiving 120 mg elementary iron daily had a significantly greater mean Hb increase than patients receiving 120 mg elementary iron alternate day.[20] In our study, the mean Hb increase at the end of week 2 was ≥ 1 g/dL in the group given twice and once daily, whereas the Hb increase was slower in the group given alternate day, and the mean Hb increase remained < 1 g/dL at week 2. This evidence concerns the gene GSTM1 and anemia (phenotype).