A simple, self-propelling particle system is disclosed that can deliver a cargo through flowing aqueous solutions. This disclosure provides a non-aqueous composition comprising: (i) particles formed of a carbonate salt and having an average diameter of about 100 μm or less and (ii) an acid in solid form. The particles may be associated with a cargo molecule or particle. In mouse models of severe hemorrhage, the propelled particles are able to deliver a procoagulant enzyme and halt bleeding.