The properties and characteristics of a variety of embolic materials (Clots--surgicel--gelfoam--barium--cyanoacrylates) were investigated by transcatheter embolization of the rat kidney. Clots and surgicel result in temporary embolization, with return of normal renal function. Gelfoam barium and cyanoacrylates produce definitive embolization. Only barium was found in veins.