Abstract: This invention provides a claycy and sticky substance as a new biomaterial that cannot be found in the current medical field, which is bioresorbable, shows tackiness, plasticity and shape holding ability at a temperature of approximately from 30 to 40° C. and can give unrestricted shapes at body temperature or more by increasing its fluidity. This clayey and sticky substance comprises a copolymer of two or more bioresorbable monomers, preferably any one of copolymers of p-dioxanone with D-lactic acid, L-lactic acid, D,L-lactic acid, trimethylene carbonate and &egr;-caprolactone, or a mixture of two or more of these copolymers. This clayey and sticky or clayey substance is suited for a hemostatic material, an adhesive material for tissues, a prosthetic material for tissue reconstruction use, a carrier of drug delivery system, a plugging material, an accretion-preventing material and a scaffold material for tissue engineering use.