Hydrothermally treated product of compound having hydrotalcite-like crystal structure composition thereof, and use thereof

A composition for increasing at least one of hemoglobin and the serum iron level, said composition comprising

• (1) an amount, effective for increasing at least one of hemoglobin and the serum iron level, of a hydrothermally treated product of a compound having a hydrotalcite-like crystal structure and represented by the following formula (I)
• (Fe.sup.2+,Mg.sup.2+).sub.x (Al.sup.3+,Fe.sup.3+).sub.2 (OH).sub.2x+6-nz (A.sup.n-).sub.z.mH.sub.2 O (I)
• wherein A.sup.n- represents an anion having a valence of n, Mg.sup.2+ is within the range of 0.ltoreq.Mg.sup.2+ <x, Fe.sup.3+ is within the range of 0.ltoreq.Fe.sup.3+ <2, x is a number represented by 1.ltoreq.x<20, z is a number represented by 0<z<3, and m is a number represented by 0.ltoreq.m<20,
• the product being formed by the thermal treatment of the compound of formula (I) at a temperature of about 100.degree. C. to about 200.degree. C. in an aqueous medium, and
• (2) a pharmaceutically acceptable diluent or carrier.