Obesity is an increasing epidemic worldwide and has a significant impact on human health and socioeconomics. Multiple studies have shown that bariatric surgery increases the risk of postoperative gallbladder stones. Contributing factors to gallstone formation include gallbladder motility and bile supersaturation due to rapid weight loss and cholesterol mobilization. At present, the prevention and treatment of gallbladder stones in obese patients after bariatric surgery are still controversial. In recent years, the study of ursodeoxycholic acid in preventing gallbladder stone formation after bariatric surgery has become a research hotspot. At the same time, other studies have shown that taking probiotics or digestive enzymes may improve gastrointestinal symptoms and improve quality of life after bariatric surgery. Therefore, the purpose of this study was to determine the ability of probiotics to prevent gallstone formation after bariatric surgery and to evaluate the impact of oral probiotics on quality of life in patients after bariatric surgery.

Inclusion Criteria:

• Patients receiving bariatric surgery for morbid obesity
• Patiets at ages between 20 to 60 y/o
• Patients willing to follow up regulary after bariatric surgery

Exclusion Criteria:

• Patients having gallstones before bariatric surgery
• Patients refusing taking probiotics or refusing regular follow up after bariatric surgery