What Causes Gallstones?

Although they are often symptom-free, gallstones can lead to abdominal pain, gas, and nausea.

Gallstones are rocklike nuisances that can form inside the gallbladder. The gallbladder is a pouch that collects bile as it flows from the liver to the intestine through the bile ducts. Bile is a fluid that is made, in part, to help with digestion. The salts in bile make it easier for you to digest fat. However, bile also contains some waste products including cholesterol and bilirubin (created when old red blood cells are destroyed). Gallstones form in the gallbladder when cholesterol or bilirubin particles begin to cluster together into a solid lump. The stone grows in size as the bile fluid washes over it, much like a pearl forms inside an oyster.

Most of the time, gallstones do not cause any symptoms or problems. Small gallstones can leave the gallbladder and pass out of the body through the intestines. However, gallstones can cause symptoms if they become caught in the narrow outlet of the gallbladder. After meals, especially meals high in fat, a muscle in the wall of the gallbladder squeezes to help empty bile into the intestines. If this muscle squeezes against a gallstone, or if a gallstone blocks the draining fluid, the gallbladder can ache with a strong, steady pain. More serious problems can develop if a gallstone gets into the drainage-duct system but does not make it all the way through to the intestines. In this case, the stone can cause a buildup of bile as well as infection in the gallbladder or liver or inflammation of the nearby pancreas.

Gallstones are very common. They occur in one out of five women by age 60, and they are half as common in men. Gallstones occur more commonly in older people and in people who are overweight or who lose weight suddenly. They also occur more frequently in women who have been exposed to higher amounts of the hormone estrogen over their lifetime by having multiple pregnancies, by taking birth control pills, or by taking hormone replacement after menopause.