Virtual screening against NF-kappaB p50 using docking simulations was applied by starting from a three-dimensional (3D) database containing more than 4.6 million commercially available structures. This database was filtered by specifying a subset of commercially available compounds sharing a (2E,Z)-3-(2-hydroxyphenyl)-2-propenoate substructure and relevant druglike properties. Docking to p50 NF-kappaB was performed with a test set of six known inhibitors of NF-kappaB-DNA interactions. In agreement with docking results, the highest-scored compound displayed a high level of inhibitory activity in electrophoretic mobility shift assay (EMSA) experiments (inhibition of NF-kappaB-DNA interactions) and on biological functions dependent on NF-kappaB activity (inhibition of IL-8 gene expression in cystic fibrosis IB3-1 cells). We found that this in silico screening approach is suitable for the identification of low-molecular-weight compounds that inhibit NF-kappaB-DNA interactions and NF-kappaB-dependent functions. Information deduced from the discovery of the new lead compound and its binding mode could result in further lead optimization resulting in more potent NF-kappaB inhibitors.