Abstract: OBJECTIVE To synthesize five esters of ketoprofen and study their anti-inflammatory activities and gastrointestinal side effects. METHODS Five compounds were synthesized by paeonol and its structural analogues with ketoprofen by DCC method; anti-inflammatory activities of the compounds were evaluated with xylene-induced mice ear swelling model and carrageenan-induced rat paw swelling test; the research about the mice gastrointestinal side effects also was explored. RESULTS Five compounds were synthesized and their structures were confirmed by ¹H-NMR and MS. Compared with the corresponding positive and negative control group, the five target compounds could significantly reduce the mice ear swelling and rat paw swelling, all compounds showed anti-inflammatory activities. Five target compounds on gastrointestinal lesion area were significantly less than positive and negative groups and significantly reduced gastrointestinal side effects. CONCLUSION Five esters of ketoprofen are synthesized. Compared with the ketoprofen, they show significant anti-inflammatory activity and obviously reduce gastrointestinal side effects.