Abstract: Methods for removing ferric iron from aqueous liquids and for performing deferration therapy are disclosed, involving the use of a novel siderophore, termed anguibactin. Anguibactin is isolated from a marine pathogen, Vibrio anguillarum, containing the pMJ1 plasmid. Anguibactin inhibits iron uptake by living cells, wrests iron from vertebrate tissues, removes iron from other siderophores and ferric hydroxide, and removes ferric iron from aqueous solutions, including cell-culture media. For deferration therapy, anguibactin from which bound iron has been removed is administered by dissolving in water or other liquid aqueous pharmaceutical carrier at a dosage typical for other siderophores. Anguibactin is preferably administered intramuscularly or subcutaneously, but can be given intravenously.