Abstract: OBJECTIVE To observe the effect of Compound Xinyi Pichuan Liquid in preventing oxidative damage. METHOD 36 male and female guinea pigs were randomly divided into a model group, a positive control group, a blank control group and three treatment groups with different dosages of medication. Egg albumen was used to make asthma models to observe the changes of SOD and MDA level. Three different dosages of drugs at different ratio were added to human embryonic lung cells to be compared with the positive control group and the blank control group. 24 hours after the use of drugs, the digestion cells were made into cell suspension to observe the changes in SOD level. RESULT The guinea pig SOD level in the asthma group was lower than the medication groups and the MDA level was higher than the medication groups, with marked significance as compared with the medication group in which large and medium dosages were used (P<0.05). The SOD level in the medication groups in which human embryonic lung cells were used increased as compared with the control group (P<0.01). CONCLUSION Compound Xinyi Pingchuan Liquid has the effect of preventing oxidative damage.