<jats:title>Abstract</jats:title><jats:p>Three new amides, pipgulzarine (<jats:bold>1</jats:bold>), pipzorine (<jats:bold>2</jats:bold>), and piptahsine (<jats:bold>3</jats:bold>), have been isolated from the dried seeds of <jats:italic>Piper nigrum</jats:italic> L<jats:sc>inn.</jats:sc> along with nine known constituents: (2<jats:italic>E</jats:italic>,4<jats:italic>E</jats:italic>,8<jats:italic>Z</jats:italic>)‐<jats:italic>N</jats:italic>‐(isobutyl)eicosatrienamide, pellitorine, pipercide, piperine, stigmastanol, stigmasterol, decurrenal, stigmasterol 3‐<jats:italic>O</jats:italic>‐<jats:italic>β</jats:italic>‐<jats:sc>D</jats:sc>‐glucopyranoside, and 5,10(15)‐cadinen‐4‐ol. The structures of the new constituents have been established as <jats:italic>(2</jats:italic>E<jats:italic>,11</jats:italic>E<jats:italic>)‐12‐(benzo[1,3]dioxol‐5‐yl)‐</jats:italic>N<jats:italic>‐(2‐methylpropyl)dodeca‐2,11‐dienamide</jats:italic> (<jats:bold>1</jats:bold>), <jats:italic>(2</jats:italic>E<jats:italic>,12</jats:italic>Z<jats:italic>)‐</jats:italic>N<jats:italic>‐(4‐methylpentyl)octadeca‐2,12‐dienamide</jats:italic> (<jats:bold>2</jats:bold>), and <jats:italic>(2</jats:italic>E<jats:italic>,4</jats:italic>S<jats:italic>)‐4‐hydroxy‐</jats:italic>N<jats:italic>‐(2‐methylpropyl)hex‐2‐enamide</jats:italic> (<jats:bold>3</jats:bold>). The structures of <jats:bold>1</jats:bold>–<jats:bold>3</jats:bold> were derived by spectral studies and chemical reactions, and by comparison of spectral data in the case of known constituents. Compounds <jats:bold>1</jats:bold> and <jats:bold>2</jats:bold>, and most of the already known compounds, exhibited toxicity against fourth instar larvae of <jats:italic>Aedes aegypti</jats:italic> Liston. The isolated <jats:italic>(Z</jats:italic>) double bond in <jats:bold>2</jats:bold> was assigned on the basis of its EI‐MS fragmentation pattern and its reaction with OsO<jats:sub>4</jats:sub>. The (<jats:italic>S</jats:italic>) configuration at C(4) of <jats:bold>3</jats:bold> was determined by <jats:italic>Horeau</jats:italic>'s method. This is the first report of the isolation of a 4‐methylpentylamide from <jats:italic>P. nigrum</jats:italic>, while shorter branched amides have been reported from this genus [1].