Abstract: To observe the effects of phenylallyl compounds on prostaglandin E₂(PGE₂)release in mouse cerebral microvascular endothelial cells (bEnd.3) stimulated by IL-1^β, and to analyze their structure-activity relationship. Different concentrations of phenylallyl compounds were added separately, and the content of PGE₂ induced by IL-1β 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-1β. 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-1β and presented certain structure-activity relationship.