Hepatic blood flow has been investigated using color Doppler ultrasonography in patients with liver disease, especially in patients with portal hypertension (e. g. liver cirrhosis, portal vein thrombosis, Budd-Chiari-syndrome). Duplex examination protocols, however, differ considerably because no standard technique has been established so far. Whereas there is an agreement about the angle of the ultrasound application (< 60 degrees ), neither the exact location nor the relevant examination parameters have been standardized. Based on a search of the relevant literature, published examination techniques and results were analyzed. These findings are to serve as a basis for a prospective multicenter study for the determination of standard values.