A new amide, Δαβ-dihydropiperine (I), has been isolated from the wood of Piper novae-hollandiae and synthesized. Two amides, N-isobutyl-trans- 2,trans-4-octadienamide and 3,4-methylenedioxycinnamoylpiperidide, previously unreported from natural sources but known from synthesis, were present as were five amides already established as plant constituents, namely, N-isobutyl-trans-2,trans-4-decadienamide, fagaramide, piperlonguminine, piperine, and an isomer of piperine, probably chavicine, as well as the essential oil, dillapiole. Δαβ-and Δβγ-Dihydro-piperlonguminine, (VIII) and (IX), and Δβγ-dihydropiperine (III) were also synthesized.