Abstract: For reducing the health risk of smoking, the antioxidant activity of a mixture of Flos Sophorae immaturus concrete and day-lily concrete was determined, the acute toxical death experiments of SPF mouse and Wistar rats exposed to the mainstream smoke of cigarettes added with a mixture of Flos Sophorae immaturus concrete, day-lily concrete, cellulase and neutral proteinase were conducted, and the sections of heart, lung and liver from dead rats were histopathologically examined as well.The results showed that:1) the two concretes were strong in scavenging the free radicals, ·OH and ·O₂^-, and 2) comparing with the control, the rats exposed to mainstream smoke of cigarette spiked with the mixture survived significantly longer and their internal organs were obviously less injured.