At present obesity is a major public health challenge globally, which accounts for a significant portion of all healthcare costs. Obesity and its complications, insulin resistance and dyslipidemia, have been identified as independent risk factors for cholelithiasis. Cholelithiasis is mainly caused by four factors: bile cholesterol overload caused by excess cholesterol made in the liver due to genetic factors; systolic dysfunction of the gallbladder wall; bowel dysfunction with excess absorption of cholesterol or cholesterol overload caused by impaired hepatic bile circulation; and accelerated growth of cholesterol crystals and solid cholesterol crystals. Rapid weight loss (≥1.5 kg/week) due to low-calorie diets as the main treatment method, or after bariatric surgery is one of the risk factors for gallstone formation. Bariatric surgery is effective for the treatment of obesity and its complications, but bariatric surgery does not reduce the incidence of cholelithiasis. On the contrary, many studies showed that bariatric surgery may increase the incidence of cholelithiasis. The rapid weight loss causes fat mobilization and then increases serum cholesterol and triglyceride levels. On the other hand, bowel dysfunction due to bariatric surgery is accompanied by decreased cholecystokinin levels, causing impaired gallbladder contractility. Cholelithiasis requires close attention after bariatric surgery, with 10% of patients undergoing bariatric surgery having to undergo cholecystectomy postoperatively due to a high risk of cholelithiasis. UDCA is a natural bile acid that is prescribed to be taken orally (by mouth). UDCA inhibits the absorption of cholesterol in the bowel, enhances the biosynthesis of bile acids, and reduces biliary cholesterol secretion. UDCA is a choleretic agent, as all bile acids, but differs from other dihydroxy bile acids in being non-cytotoxic. The use of UDCA while following a low-calorie diet and after bariatric surgery significantly reduces the risk of gallstone formation and cholecystectomy with associated complications.