Gallstones, or as we call it in medical terms cholelithiasis, are solid particles formed when substances in the bile harden.Cholesterol gallstone often appears yellow in color. These gallstones are composed mainly of undissolved cholesterol, but may contain other components.They can be numerous involving as many as hundreds of small stones, or can be as big as ones mind can imagine. They cause severe obstruction and perforation of the gallbladder, subsequently leading to inflammation of the area and episodes of prolonged sharp colicky pain in he right upper quadrant of the abdomen. In cases of severe inflammation, gallstones this size are unable to pass through the bile duct and may erode through the gallbladder wall into adherent bowel potentially causing an obstruction termed gallstone ileus. Ideally, once gallstones become symptomatic, definitive surgical intervention with cholecystectomy is usually indicated (typically, laparoscopic cholecystectomy).