(HealthDay News) -- Gallstones are stones of varied sizes that form in the gallbladder, and are usually composed of cholesterol or excess bilirubin in the bile. Some gallstones cause no symptoms, while others can cause significant pain.

The U.S. National Library of Medicine offers this list of gallstone warning signs:

• Pain that occurs in the upper-right or upper-middle abdominal area. It may come and go, and may be more noticeable after you eat.
• Pain that spreads to the back or beneath the right shoulder blade.
• Pain that feels dull, crampy or sharp.
• Pain accompanied by fever or jaundice (yellowing of eyes and skin).
• Nausea or vomiting.
• Passing stools the color of clay.

• More News on Gallstones

Related MedlinePlus Pages:

• Gallstones