The gallbladder is a pear-shaped organ that collects and stores bile, a digestive fluid produced by the liver. Unfortunately, our gallbladders do not always work right. When they fail to function properly and allow too much bile and cholesterol to accumulate, gallstones may form.  Gallstones are typically either made of cholesterol (Cholesterol Stones) or bile (Pigment Stones). Both forms can be very painful when they block a bile duct.