A method for medical treatment was developed in which microspheres with novel properties are administered in a mammal. The microspheres are made using a novel process that results in microspheres with new combined properties of high density, low fracture, high swell capacity, rapid swell, and deformability following swell. These microspheres may be administered for void filling, tissue bulking, non-vasculature occlusion, body fluid absorption, and delivery of medications.