The gallbladder is a small sac located on the right-hand side of the human body, on the lowerside of the liver. Some of the chemicals that exist in the gallbladder can solidify into either one large stone or several small ones. These stones are called gall stones. Gallstones are stones or lumps that develop in the gallbladder or bile duct when certain substances harden.

Gallstones within the gallbladder often cause no problems. If there are many or they are large, then they may cause pain when the gallbladder responds to a fatty meal. They also may cause problems move out of the gallbladder and block the bile duct or they block bile from leaving the gallbladder.