Linear densities which were thought to represent meglumine iodipamide were seen in the renal papillary tubules of three patients for respectively four, six and nine days following intravenous cholangiography (IVC). All three patients were children with hepato-biliary disease. Two patients had biliary roundworm infestation, and one patient had hepatic dysfunction and intestinal ascariasis with possible biliary involvement. Haematuria and renal enlargement were seen in one patient, but the cholangiogram was not conclusively implicated as a cause. This renal tubular "sludging" of biliary contrast medium is recorded because of its potential nephrotoxic significance. The possible causes are discussed.