Aims: This study investigated the effect of a series of naturally occurring aliphatic (2E)-alkenals against Salmonella choleraesuis subsp. choleraesuis ATCC 35640 and evaluated their antibacterial action. Method and Results: A homologous series of aliphatic (2E)-alkenals from C-5-C-13 were tested for their antibacterial activity against Salm. Choleraesuis. The antibacterial action of (2E)-alkenals against Salm. choleraesuis increases with increasing carbon chain length. (2E)-Dodecenal (C-12) was the most effective against this food-borne bacterium with minimum bactericidal concentration (MBC) of 6.25 mug ml(-1) (34 mumol l(-1)), followed by (2E)-undecenal (C-11) with an MBC of 12.5 mug ml(-1) (77 mumol l(-1)). The activity was found to correlate with the hydrophobic alkyl chain length from the hydrophilic aldehyde group. The time-kill curve study showed that (2E)-dodecenal was bactericidal against Salm. choleraesuis at any growth stage. Conclusions: The antibacterial activity of (2E)-alkenals against Salm. choleraesuis was found to correlate with the hydrophobic alkyl chain length. The conjugated double bond is not essential in eliciting the activity but is associated with increasing it. Significance and Impact of the Study: Because of their easy availability and wide distribution in many edible plants, (2E)-alkenals can be used as anti-Salmonella agents.