Yuehchukene, a novel dimeric indole alkaloid with potent anti-implantation activity has been isolated from the roots of Murraya paniculata and identified as a racemic mixture of 6β-(3′-indolyl)-7α,7β,9-trimethyl- 6aβ,7,8,10aβ-tetrahydroindeno[2,1-b]indole (1) and its enantiomer.