Gallstones: Definition, Symptoms, Treatments

Illustration of gallstones
An illustration of gallstones. PIXOLOGICSTUDIO/SCIENCE PHOTO LIBRARY/Getty Images

Gallstones are collections of material that can form inside the gallbladder. Some gallstones form when there is too much cholesterol in the bile, while others may form if there are not enough bile salts. Gallstones may also form if the gallbladder does not empty properly. Obesity is a known risk factor for developing gallstones.

What Are Gallstones?

You may have heard a friend or family member complain that they have had gallstones.

The name makes the condition sound as if rocks have formed inside your loved one's body. But the condition is a little more complicated than that.

Gallstones form when solid material collects and builds in the gallbladder. The gallbladder is a pear-shaped organ that sits in your upper abdomen. The gallbladder stores a substance called bile and aids in the process of digestion.

Gallstones can vary in size, but they are not usually as big as a real stone. According to the National Institutes of Health, some are as small as a grain of sand while others can be as large as a golf ball. Gallstones that cause no symptoms are called silent gallstones or asymptomatic gallstones. But some may cause pain. These are called symptomatic gallstones.  

What Are Gallstones Made Of?

There are two different types of gallstones. Each type of gallstone is made of a different substance. 

  • Cholesterol gallstones are most common. They form when there is too much-hardened cholesterol in the bile. These stones are yellow-green in color.
  • Pigment gallstones are less common and are made of bilirubin, a yellow-brown substance that is produced during normal body processes.

What Are the Symptoms of Gallstones?

Symptoms of gallstones may range from mild (some are not noticeable at all) to severe.  When gallstones cause painful symptoms it is called a gallstone attack.

Symptoms of gallstones or a gallstone attack may include:

  • Severe pain in the upper right side of the abdomen that starts suddenly and lasts from 30 minutes to several hours
  • Pain under the right shoulder or in the right shoulder blade
  • Nausea or vomiting
  • Indigestion after eating foods high in fat or protein, including desserts and fried foods

The National Institute of Diabetes and Digestive and Kidney Diseases  also notes that gallstone attacks are more likely to  happen in the evening or at night and often occur after a heavy meal.

If you think you have had a gallstone attack, you should contact your health care provider to avoid complications. Complications of gallstones may include:

  • biliary colic, which causes episodic abdominal pain with nausea and vomiting
  • cholecystitis (infection of the gallbladder), which causes abdominal pain and fever
  • cholangitis (infection of the bile ducts), which causes yellowing of the eyes or skin, abdominal pain, and fever. This may also cause abnormal lab results.

    A low-fat diet and gradual, moderate weight loss may help prevent the development of gallstones. Treatments for gallstones, if needed, may include medication and surgery.


    Division of Nutrition, Physical Activity, and Obesity. The Health Effects of Overweight and Obesity. Centers for Disease Control and Prevention.

    Douglas O. Olsen, MD, FACS. Gallbladder Disease and the Obese Patient. Obesity Action Coalition.

    Health Information. Dieting and Gallstones. National Institute of Diabetes and Digestive and Kidney Diseases.

    Health Information. Gallstones. National Institute of Diabetes and Digestive and Kidney Diseases.

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