The invention relates to magnesium-polymer composites, methods for their preparation and applications for their use. The composites include a combination of magnesium particles and polymer matrix. The polymer can include, but is not limited to, poly(lactic co-glycolic) acid. In certain embodiments, the composites of the invention are particularly useful for forming medical devices for implantation into a body of a patient. In certain other embodiments, the magnesium-polymer composites are useful for wound healing compositions for administration to an exterior surface of a body of a patient.