To observe the effects of phenylallyl compounds on prostaglandin E2 (PGE2) release in mouse cerebral microvascular endothelial cells (bEnd. 3) stimulated by IL-1beta, and to analyze their structure-activity relationship. Different concentrations of phenylallyl compounds were added separately, and the content of PGE2 induced by IL-1beta in the culture media was measured by ELISA assay. The 50% inhibitory concentration (IC50) of PGE2 was calculated. Studies showed that phenylallyl compounds could affect the PGE2 release differently in bEnd. 3 cells induced by IL-1beta. Close relationships were shown between the inhibitory activities and the location and number of the substituent groups. In conclusion, phenylallyl compounds exhibited inhibitory activities at different extent on PGE2 release in bEnd. 3 cells stimulated by IL-1beta and presented certain structure-activity relationship.