Gallstones are crystallized accumulations of fluid formed in gallbladder. The causes of gallbladder are - Excessive synthesis of cholesterol - High bilirubin concentration in bile - Incomplete emptying of gallbladder Symptoms of gallstones include - Pain in right hypochondrium - Intense pain in the abdomen - Referred pain between the shoulders - Nausea - Vomiting - Dark urine - Indigestion - Pale, clay-colored stools - Diarrhea - Jaundice - Loss of appetite - Fever There are two types of gallstones: Pigment and cholesterol gallstones. Pigment gallstones are formed when bile contains high concentration of bilirubin. They are black or dark brown in color. Cholesterol gallstones are formed by excessive formation of cholesterol. They are yellow in color. People who are at risk of gallstones include - Females - Age over 40 - Obesity - Sedentary lifestyle followers - Pregnant females - Consumers of high-cholesterol, low-fiber and high-fat diet - Diabetics - Patients of liver disease