ITF 282 is an iron succinyl casein complex containing 5% iron. The main property of the derivative is to keep iron bonded at acidic pH values. This accounts for a better tolerability of the compound compared with iron salts, during the treatment of iron deficiency. Pharmacological studies in normal and anemic rats demonstrated that this iron complex is almost as active as ferrous sulphate against iron deficiency anemia, but it is significantly less potent in increasing serum iron. Better gastrointestinal tolerability of ITF 282 was demonstrated in rats and dogs. Chemical and pharmacological properties of iron-protein succinylate are described.