The effects of Ioxitalamate/Telebrix-BYK GULDEN were tested for excretion urography and various angiographic applications and in animal experiments (selective renal angiography in 36 dogs). The contrast medium was well tolerated and the radiographs were of good quality. Significant effects were not detected, neither in blood pressure, heart rate and ECG, nor in Se-creatinine, nor in UN-, SGOT and Se-bilirubin values. In 4 cases transient proteinuria was observed. In the kidneys of the dogs no mentionable effects, histological or ultrastructural, were found. The use of Ioxitalamate seems advisable for investigations that require contrast media with low osmotic pressure.