A hemostatic agent comprises diatomaceous earth in particle form. Devices for promoting hemostasis comprise diatomaceous earth in particle form and a receptacle for retaining the particles therein. The receptacle is defined by a mesh having openings therein. A hemostatic sponge comprises a substrate, diatomaceous earth disposed on the substrate, and a release agent disposed on the substrate. A hemostatic sponge may also comprise a film into which diatomaceous earth is incorporated, or it may comprise a substrate, diatomaceous earth disposed on the substrate, and a film disposed over the diatomaceous earth. A hemostatic sponge may also comprise a first substrate, diatomaceous earth disposed on the first substrate, and a second substrate disposed on the diatomaceous earth. When treating a bleeding wound using any of the foregoing devices, application of the device causes the diatomaceous earth to come into contact with blood to cause a clotting effect.