The authors report an experiment using the cadaver kidney with a fibrin coagulum injected into the pelvis and calices in order to extract multiple calculi. They used a mixture of cryoprecipitated plasma and a combination of thrombin and calcium chloride. This mixture was made up immediately before use, and injected into the pyelocaliceal cavities using a small Foley catheter previously inserted into the renal pelvis. This catheter was used to empty completely the pyelocaliceal cavities of urine immediately before injection. Extraction via a pyelotomy incision was used to withdraw the compact mold which had imprisoned the stones. In 20 kidneys studied experimentally, removal of stones was complete in only 12. The authors blamed this on their initial technical inexperience. The limitations and advantages of the method are discussed.