Iron-deficiency anemia and pre-anemic iron deficiency are the most frequent pathologies. The first line of treatment involves oral iron supplementation. The simplest, least expensive, and most commonly prescribed drug is ferrous sulfate, while other ferrous salts and ferric complexes with polysaccharides or succinylated milk proteins are also widely used. In recent years, novel iron formulations have been developed, such as the lipophilic iron donor ferric maltol, or nanoparticle encapsulated sucrosomial® iron. Oral iron supplementation is usually efficacious in correcting iron-deficiency anemia and replenishing iron stores but causes gastrointestinal side effects that reduce compliance. When oral iron supplementation is contraindicated, intravenous iron therapy can rapidly achieve therapeutic targets without gastrointestinal complications. Herein, we critically review literature on relative efficacy and tolerability of currently available oral iron supplements, and summarize recent data on optimal dosage and frequency.