Cholecystitis is the inflammation of the gallbladder, a small organ located beneath the liver that stores bile. This condition often occurs when a gallstone blocks the cystic duct, leading to a buildup of bile and increased pressure in the gallbladder. Symptoms may include severe abdominal pain, nausea, vomiting, and fever. There are two main types of cholecystitis: acute and chronic. Acute cholecystitis develops suddenly and is usually caused by gallstones, while chronic cholecystitis results from repeated episodes of inflammation. Treatment often involves medication, dietary changes, or surgery to remove the gallbladder, known as a cholecystectomy.