Background: Bile acids are endogenous ligands of nuclear and cell membrane receptors that are important in bile acid and lipid metabolism. They are detergents that create bile flow and facilitate intestinal absorption of fat and fat-soluble vitamins. Bile acids are naturally synthesized in the liver and end products of cholesterol catabolism. Bile acids and their metabolites are important ligands that interact with several nuclear receptors and cell membrane receptors such as Farnesoid X receptor and G-protein coupled bile acid receptor 1. Nowadays, many studies focus on bile acid species for targeting nuclear receptors in GI system to improve treatment of such illness like Non-alcoholic fatty liver disease. 

Purpose: The purpose of this research is to review existing literature on bile acids and their roles in treating various diseases. 

Methods: Collect data using various trusted research websites, evaluate collected data, write drafts, and draw figures using bio render website, and for references we will use EndNote program. 

Expected Result: Since this topic was taken into the account by many research groups around the world. This topic is considered as a new topic because of that lack of or incomplete data will be expected. 

Conclusions: Bile acid as a therapy is an important due to their ability in activation or inhibition of nuclear receptors such as Farnesoid X receptor. This research will provide needed information for scientists and medical practioner who are interested in finding new studies that show importance of bile acids in improving and limiting disorder progression. This study will also leave the way open to previously neglected bile acid-based therapy.