Gallstones are stones or lumps that develop in the gallbladder or bile duct when certain substances harden. The gallbladder is a small sac located on the right-hand side of the body, on the underside of the liver. Some of the chemicals that exist in the gallbladder can solidify into either one large stone or several small ones. Fast facts on gallstones Here are some key points about gallstones. More detail and supporting information is in the main article. The gallbladder is a small organ located on the underside of the liver. Stones can form when there is a chemical imbalance in the gallbladder. People with overweight and obesity are more likely to develop gallstones. Experts believe a low-fat, high-fiber diet may help prevent gallstones. Symptoms Gallstone pain Symptoms of gallstones may include pain on the right-hand side of the body. The majority of people with gallstones experience no symptoms at all. This is because the stones stay in the gallbladder and cause no problems. Sometimes, however, gallstones may lead to cholecystitis, or an inflamed gallbladder. The primary symptom is pain that comes on suddenly and quickly gets worse. This pain can occur on the right side of the body, just below the ribs, between the shoulder blades, or in the right shoulder. Other symptoms include: pain on the right-hand side of the body, just below the ribs back pain between the shoulder blades pain in the right shoulder nausea vomiting sweating restlessness