A composition and method of arresting the flow of blood from a bleeding wound. The composition preferably includes an anhydrous salt ferrate compound preferably combined with an effective amount of an insoluble cation exchange material and an effective amount of anhydrous Magnetite mixed uniformly together. Povidone iodine may be added for enhanced antimicrobial properties. In the method, a quantity of the composition is magnetically attached to a surface of a magnet, after which the powderous mixture is applied to the wound by pressing the surface covered with the powderous compound against the wound for a time sufficient to clot the blood to arrest substantial further blood flow from the wound.