Extracting saponins from the bulbs of lilium,in a stable system of Fe 2+-H 2O 2 producing hydroxyl radical,bromopyrogallol red is added to determine the absorbance change by means of spectrometry. The scavenging effect of saponins in lilium extraction on hydroxyl radical is studied in this system. The effect of this method is concluded by comparing the scavenging effect of ordinary antioxidants. The result shows that saponins of lilium has a good scavenging effect on hydroxyl radical. This method prov...