PD 168368 is a selective, nonpeptide antagonist of the neuromedin B receptor (NMB-R) and an inhibitor of the gastrin-releasing peptide receptor (GRPR). It also acts as a potent mixed agonist for FPR1, FPR2, and FPR3. This compound is a valuable research tool for studying receptor signaling in cancer, inflammation, and neurobiology using both in vitro and in vivo models.