Gallstones are stones that form in the gallbladder. Most gallstones are crystals of cholesterol. Cholesterol is a waxy substance used for many body processes. Gallstones may also be crystals of calcium and bilirubin. Bilirubin is a by-product formed when red blood cells break down.

What is going on in the body?

The gallbladder stores bile. Bile is a liquid produced in the liver that aids in digestion. When a person eats, bile flows through a series of tubes or ducts into the intestines. It helps to break up food so that it can be used by the body. When bile is supersaturated with cholesterol or bilirubin, it may form the crystals known as gallstones.

What are the causes and risks of the condition?

Gallstones are crystals that form from excess cholesterol or bilirubin. Factors that increase a person's risk for gallstones include: