Cocculus lauriforius DC. (Menispermaceae), an evergreen shrub, is a rich source of a variety of alkaloids1) such as erythrinans, 1-benzyltetrahydroisoquinolines, aporphines, and dibenz [d,f] azonines, and extensive investigations on its alkaloidal constituents have been carried out. We have examined the constituents of the leaves of this plant collected at Ishigaki Island (Okinawa, Japan) and isolated a novel nonalkaloidal component, named coclauril (1). Its structure was assigned as a geometrical isomer of the aglycone of menisdaurin (3),2) a cyanoglucoside isolated from Menispermum dauricum DC. (Menispermaceae). In addition, two known bicyclic butenolides, menisdaurilide (8)2,3 and aquilegiolide (9)3 were shown to co-occur with coclauril (1) and were characterized. However, no alkaloidal component could be detected.