The gall-bladder is a pear-shaped organ, 10 cm. long and three to five cm. wide, attached to the under-surface of the liver on the right side. The main function of the gall-bladder is to store the bile secreted by the liver. Bile is an excretion composed mainly of bile salts and acids, colour pigments and cholesterol. Bile assists in the digestion and absorption of fats and the absorption of fat-soluble vitamins A, D, E and K, minerals and calcium.

The gall-bladder is usually full and relaxed between meals. During the process of digestion, when food reaches the duodenum, the hormone cholecystokinin begins to be produced in the internal mucosa. When this hormone reaches the gall- bladder through the bloodstream, it causes the gall-bladder to contract, thereby releasing the bile concentrate into the duodenum via a common duct.

The main problems which afflict the gall-bladder are an inflammatory condition known as cholecystitis and gall-stones. Gall-stones are usually caused by disturbances in the composition of the bile. A change in the ratio of cholesterol and bile salts may result in the formation of deposits. At the start, these may be in the form of fine gravel. But these fine particle constitute the nucleus for further deposits, ultimately leading to the formation of larger stones. An irritation of the lining of the gall- bladder due to inflammation may also led to the formation of particles.

The incidence of gall-stones is higher in females than males, particularly in those who are obese.