Fifty patients were analyzed after a randomized double-blind study comparing Hexabrix and Hexabrix-20 in ascending phlebography. Measures of safety and patient tolerance indicated that both concentrations of Hexabrix appeared safe and were well tolerated. All studies were diagnostic, and the image quality was rated as excellent in 80% of the Hexabrix group and 72% of the Hexabrix-20 group. The authors conclude that Hexabrix and Hexabrix-20 are acceptable contrast media for ascending phlebography.