PURPOSE: To obtain a remedy for hypoferremia, having higher stability and preservability than a product without hydrothermal treatment, and exhibiting remarkable effect, by forming a specific compound having a crystal structure similar to hydrotalcite, and subjecting the compound to the hydrothermal treatment in an aqueous medium at a specific temperature.

CONSTITUTION: A compound of formula I (An- is n-valent anion; 0≤Mg2+<x; 0≤Fe3+<2; 1≤x<20; 0<Z<3: 0≤m<20) having a crystal structure similar to hydrotalcite, is subjected to the hydrothermal treatment in an aqueous medium at about 100W200°C, and the treated product is used as an active component of a remedy for hypoferremia. The compound of formula I is preferably the compound of formula II. The compound of formula I can be prepared e.g. by reacting an aqueous solution of a water-soluble Fe(II) salt with an aqueous solution of a water-soluble Al compound under alkaline condition of ≥6pH in a nonoxidative atmosphere. The remedy has high activity and durability, and low side effects.