Cholecystitis (ko-luh-sis-TIE-tis) is inflammation of the gallbladder. Your gallbladder is a small, pear-shaped organ on the right side of your abdomen, beneath your liver. The gallbladder holds a digestive fluid that's released into your small intestine (bile).
In most cases, gallstones blocking the tube leading out of your gallbladder cause cholecystitis. This results in a bile buildup that can cause inflammation. Other causes of cholecystitis include bile duct problems and tumors.
If left untreated, cholecystitis can lead to serious, sometimes life-threatening complications, such as a gallbladder rupture. Treatment for cholecystitis often involves gallbladder removal.