The Rapid Bladder Filling Agent (RBFA) was prepared with Polyporus umbellatus, Poria cocos and Furosemidum. The urinary volume and the best filling time of urinary bladder were observed with ultrasonography in 211 cases. The result showed that in experimental group the largest urinary volume in unit time was more than that in control group and shortest filling time was shorter (30.35 +/- 7.9 min) in comparing with control group (145.6 +/- 50.1 min). Clinical observation for 1180 cases proved that the RBFA had the effects of raising the quality of ultrasonographic examination and escalating work efficiency, shortening the waiting time of patients and relieving patients' suffering from excessive filling of urinary bladder. The effective time of the RBFA was fast but the duration was short. The RBFA had no adverse effect.