**Abstract**

Gallbladder cancer (GBC) is associated with a sinister prognosis, a short survival time, and early metastasis to distant sites. Chronic inflammation of the gallbladder due to gallstone disease and biliary bacteria remain key factors in the pathogenesis of GBC. The association of chronic bacterial infections with the development of GBC has provided a new perspective on the causation of GBC. A strong link between chronic Salmonella infection and enterohepatic strains of Helicobacter species with GBC has been suggested. It is believed that many other enteric bacterial strains, predominantly the Enterobacteriaceae species, are associated with the development of GBC. However, the available literature mainly comprises observational studies and small meta-analyses necessitating the requirement of a higher level of evidence. This chapter discusses the role of the gut microbiome, dysbiosis and its association with carcinogenesis, and the organisms associated with the causation of GBC.

**Keywords:** gallbladder neoplasm, dysbiosis, gut microbiome, brain-gut axis, gastrointestinal microbiome
