Various compositions of matter, methods of making compositions of matter, and methods of using compositions of matter, e.g. for inducing hemostasis, are disclosed. In some embodiments, a starting fibrin material is subjected to controlled hydrolysis, desirably base-catalyzed, to prepare a fibrin hydrolysate material with increased water sorption capacity. Such fibrin hydrolysate materials, alone or combined with one or more additional substances, can be used in the preparation of hemostasis promoting foams, powders or gels. In some embodiments, a starting dialdehyde starch material is subjected to controlled hydrolysis to prepare a dialdehyde starch hydrolysate material. Such dialdehyde starch hydrolysate materials, alone or combined with one or more additional substances, in some cases combined with a fibrin hydrolysate material, can be used in the preparation of hemostasis promoting foams, powders or gels.