In Heilmeyer's iron-loading test the iron preparation SA (Eryfer) proved greatly superior to a commercially available effervescent tablet (iron preparation SC), to an iron preparation in a sustained release from (iron preparation SD) and to an iron preparation in the form of enteric-coated pellets (iron preparation SE), in producing and maintaining an increased serum iron level. As compared to a sodium bicarbonate-free preparation (iron preparation SB) the iron preparation SA must be considered equivalent. The results of our investigations made with iron preparation SA are supported by experiences made by other authors with therapeutic application.