a flowable , biodegradable endovascular embolic composition effective for embolizing a vascular defect consisting essentially of : a biocompatible , biodegradable polymer or polymeric material forming composition ; a biocompatible embolic solvent for the polymer or polymer forming composition capable of diffusion into mammalian tissue ; biocompatible magnetic particles responsive to a magnetic field ; wherein : the polymer or polymeric forming material and solvent are present in the composition in amounts and relative proportions such that the composition is deliverable to a vascular defect site and upon delivery to the site , solidifies into an embolic mass ; and the magnetic particles are present in the composition in an amount sufficient to enable the composition being deliverable to the vascular site by a magnetic field . also disclosed are methods and articles of manufacture embodying the above - described composition .