The chemistry of iron-gall ink and the corrosion caused by it is explained and its history revealed. The chemical structure of phytate and the way in which it neutralizes the catalytic activity of the free iron (II) ions is sketched. The results of a combined treatment with phytate, against the oxidative degradation of cellulose, and Ca resp. Mg bicarbonate against hydrolytic degradation are presented. The resulting treated papers were tested using the bursting strength test and the distributions of iron, sulphur and phosphorus over a cross-section of an ink line were examined using SEM-EDX. The yellowness index of the treated papers was measured. The results point out that treatment with an aqueous solution of calcium ammonium phytate, followed by a deacidification with aqueous calcium bicarbonate is most effective in arresting the ink corrosion process. The use of magnewium salts leads to high pH values and to yellowing of the paper. A factor in the success of the aqueous treatment is the washing out of harmful iron (II) and iron (III) ions, which is not achieved in a non-aqueous treatment.