Gallstones form when there is an imbalance in the composition of bile resulting in precipitation of one or more of its components. Between 37 and 86% of gallstones are cholesterol-rich stones, 2-27% are pigment stones and 4-16% are mixed. Cholesterol-rich gallstones are more common in Europe and North America. This has been attributed to obesity and diets containing a high proportion of refined carbohydrates and fat. Low-calorie diets and rapid weight loss are also associated with cholesterol-rich gallstones. Gallstone disease increases with age. Women have a higher prevalence of gallstones than men, which is attributed to exposure to oestrogen and progesterone. Of those with gallstones, around 1 to 4% will develop symptoms annually. Most patients (> 80%) will remain asymptomatic throughout their lifetime and the likelihood of developing symptoms diminishes with time. Liver function tests and an abdominal ultrasound should be offered to patients with symptoms suggestive of gallstone disease (e.g. abdominal pain, jaundice, fever). They should also be considered in patients with less typical but chronic abdominal or gastrointestinal symptoms. In patients with acute pancreatitis and evidence of ongoing bile duct obstruction and/or cholangitis, endoscopic retrograde cholangio-pancreatography and biliary sphincterotomy is recommended within 24-72 hours of the onset of symptoms. Patients with acute cholecystitis should be referred for laparoscopic cholecystectomy.