We hypothesize that IBD patients with mild (10 g/dL < Hb < 13 g/dL) and moderate (8 g/dL < Hb < 10 g/dL) anemia may first undergo oral iron supplementation, preferably with ferric maltol, as post-marketing studies confirmed the effective and safe drug profile (Figure 1) [25,26,27]. Here, GSTM1 is linked to anemia (phenotype).