Gallstone.

Gallstones (known medically as cholelithiasis) are hard, rock-like particles that form within the gallbladder and may become lodged into the passageways that lead from the gallbladder to the pancreas or small intestine. Gallstones are fairly common in the United States, as an estimated 10–15 percent of all American adults have developed gallstones. However, gallstones are disproportionately more common among certain groups than others. Women are more likely to develop gallstones than men, and gallstones are much more common among senior citizens than among younger people. Certain American Indian ethnic groups and Mexican Americans have higher rates of gallstones. Furthermore, persons who are overweight or obese are much more likely to develop gallstones than persons who maintain an average body weight. Although gallstones may sound like a serious medical condition—and although gallstones can lead to intense pain in individuals—gallstones are usually not harmful or life-threatening, and they can usually be treated easily.