PURPOSE: To determine the histopathologic changes occurring in normal pig organs after percutaneous injection of hot saline. MATERIALS AND METHODS: Under sonographic guidance, the livers, the gallbladders, kidneys, stomachs, and lungs of ten pigs weighing 15-20kg were punctured with a fine needle. Physiologic saline mixed with contrast medium and Lipiodol was heated to 100 degreeC and injected under fluoroscopic guidance. One to four weeks after injection, the animals were sacrificed and histopathologic examination was performed to investigate acute and chronic tissue responses. RESULTS: In all organs, coagulation necroses developed during the acute phase. Histopathologic changes observed four weeks after injection were as follows: in the liver, most damage was restored, though central necrosis persisted; in the kidney, parenchymal and uroepithelial damage fully recovered, and in the gallbladder and stomach, superficially located damage also fully recovered. In the lung, however, extensive pneumonic infiltration developed during the chronic phase. Fluoroscpoic examination revealed that saline in the liver or kidneys tended to leak easily into blood vessels, the bile duct, or ureter, and corresponding regions showed mild to moderate damage during the acute phase which fully recovered in the chronic phase. CONCLUSION: In normal pigs, significant chronic damage after the injection of hot saline mixture occurred only in the lungs.