The gallbladder is a small sac that holds bile, a digestive juice produced by the liver, that is used in the breakdown of dietary fats. The gallbladder extracts water from its store of bile until the liquid becomes highly concentrated. The presence of fatty foods triggers the gallbladder to squeeze its bile concentrate into the small intestine.

Gallstones (biliary calculi) are small stones made from cholesterol, bile pigment and calcium salts, usually in a mixture that forms in the gallbladder. They are a common disorder of the digestive system, and affect around 15 per cent of people aged 50 years and over.

Some things that may cause gallstones to form include the crystallisation of excess cholesterol in bile and the failure of the gallbladder to empty completely. In most cases, gallstones don’t cause any problems. However, you might need prompt treatment if stones block ducts and cause complications such as infections or inflammation of the pancreas (pancreatitis).

Surgeons may remove your gallbladder (called a cholecystectomy) if gallstones (or other types of gallbladder disease) are causing problems. Techniques include laparoscopic (‘keyhole’) cholecystectomy or open surgery. The gallbladder is not a vital organ, so your body can cope quite well without it.

Symptoms of Gallstones

In approximately 70 per cent of cases, gallstones cause no symptoms. The symptoms of gallstones may include:

• pain in the abdomen and back. Pain is generally infrequent, but severe
• increase in abdominal pain after eating a fatty meal
• jaundice
• fever and pain, if the gallbladder or bile duct becomes infected.

Types of Gallstones

There are three main types of gallstones:

• mixed stones – the most common type. They are made up of cholesterol and salts. Mixed stones tend to develop in batches
• cholesterol stones – made up mainly of cholesterol, a fat-like substance that is crucial to many metabolic processes. Cholesterol stones can grow large enough to block bile ducts