Stabilized multi-component antimicrobial compositions for treating tissue diseases, infections or conditions include a first and second set of differently sized and/or differently shaped metal nanoparticles, and a stabilizing agent. Compositions and treatment methods may be used for treating tissue diseases, infections or conditions caused by microbial infections, such as bacteria, viral, and/or fungal infections, or for preventing the infection of a wound, such as a cut, abrasion, ulcer, lesion, sore, and the like. The compositions and treatment methods disclosed herein may also be used as a prophylactic, and in some embodiments may be applied to otherwise healthy tissue in order to prevent or reduce the occurrence of a tissue disease, infection or condition.