In medical terms it is called coli theathiasis or gallstone. Gallstones account for 10 to 20 percent of the total population in North-South America. Gallstones are rare in Africa. People in North America suffer more from gallstones. Among the Asians, gallstones have also been reported lately. The incidence of gallstones is twice as high in women as in men. Beautiful , obese and fertile women are more prone to gallstones. However, according to a survey of 1,515 patients in Bangladesh , there were 498 beautiful women , 605 brown and 413 black. Birth control pills increase the risk of gallstones , diabetes , liver cirrhosis , intestinal disturbances , and frequent pregnancies. Most gallstones are made up of cholesterol and some gallstones. Cholesterol is the main component of gallstones. Apart from cholesterol, other elements like calcium bilirubinate , phosphate etc. are dissolved in bile. Chemicals in our body such as phospholipids and copper salts dissolve cholesterol in the gallbladder. If the balance of any type of cholesterol and these chemicals is changed, then the cholesterol becomes less soluble and starts to accumulate. In this way cholesterol accumulates and forms gallstones. Not much is known about the mechanism of pigment formation. However, such stones are formed when the bile is infected. Black stones are made up of calcium bilirubinate , mucin glycoprotein , calcium phosphate etc.