Under physiological conditions, ferric ions are essentially insoluble because of the formation of polynuclear hydroxo-bridged complexes. Ferrous ions are more soluble but may produce hydroxyl radicals on reaction with hydrogen peroxide. Chelation of ferric and ferrous ions with organic ligands may prevent these undesirable reactions. Alternatively, iron(III)-hydroxide/oxide can be stabilized and solubilized by tight interactions with carbohydrates. The data presented in this work show that, because of its physicochemical properties, the iron(III)-hydroxide polymaltose complex (IPC, Maltofer) does not interact with the active ingredients of commonly used drugs such as acetylsalicylic acid (CAS 50-78-2), tetracycline hydrochloride (CAS 64-75-5), calcium hydrogen-phosphate (CAS 7757-93-9), methyl-L-dopa sesquihydrate (CAS 41372-08-1), and magnesium-L-aspartate hydrochloride (CAS 28184-71-6). In contrast, as confirmed by calculations using thermodynamic parameters, FeCl3 x 6H2O (CAS 10025-77-1) can form different types of complexes with these substances. Moreover, the data show that under aerobic conditions high concentrations of ascorbic acid (CAS 50-81-7) can lead to mobilization of iron from IPC and, thus, support the observation that orange juice slightly increases the uptake of iron from IPC.