Taste-signaling proteins, which are expressed in the oral cavity and the gastrointestinal tract, may be involved in regulating metabolism and immunity via oral-gut-brain circuit. This study aimed to determine if these genes are expressed and altered in the jejunum of patients with extreme obesity after bariatric surgery. Reverse transcription polymerase chain reaction revealed that phospholipase C beta 2 and transient receptor potential channel M5 expressions were downregulated whereas Gustducins expression level remained unchained in the jejunum of patients with a body mass index >50. Our data suggest that taste-signaling dysregulation might contribute to obesity.