In the hierarchy of digestive organs, you might first list the stomach, liver, or colon. But there’s a pear-shaped sac tucked under your liver that barely gets a second thought: the lowly gallbladder.

This small but mighty organ plays an important role in helping us digest food, but we often don’t acknowledge it unless something goes wrong — which happens in about 15% of American adults, according to the National Institutes of Health (NIH). Yet gallbladder disease — which includes stones, inflammation, infection, or blockage — can lead to excruciating pain or even life-threatening complications down the line.

The gallbladder essentially serves as a storage room for bile, squeezing the fluid into the small intestine to help digest the fats we consume. It makes sense, then, that the organ might struggle when our diet is heavy in fatty or fried foods. We can live without a gallbladder, but it can’t stay in peak performance mode without diligent care, says Dr. William Brugge, a professor of medicine at Harvard Medical School.

“I think people generally try to ignore their gallbladder,” Dr. Brugge says. “It doesn’t have as squeamish a reputation as the colon or rectum, but it’s down there on the list.”

Risk factors

Aside from a high-fat diet, other risk factors for gallbladder disease include overweight or obesity, a family history of gallbladder issues, Native American or Latino heritage, and being 40 or older. Women are twice as likely as men to develop gallstones, which top the list of gallbladder problems. Extra estrogen, particularly during pregnancy, slows the gallbladder’s ability to empty, letting bile pool, Dr. Brugge says.

Gallstones develop when bile or related fluids form hardened stonelike lumps that can grow and multiply. Attacks of agonizing pain result when gallstones get larger or block bile ducts. Other symptoms include pain between the shoulder blades, nausea, vomiting, fever, chills, bloating, indigestion, and sweating. About a quarter of people diagnosed with gallstones each year need treatment, which is usually surgery.

“After eating a particularly heavy or fatty meal, you may have severe pain — far more than gas or cramps — that might last for an hour or two,” Dr. Brugge says.

Serious complications

Because bile ducts connect the gallbladder to other digestive organs, these surrounding structures can also suffer complications from gallbladder disease. Problems include cholangitis (bile duct inflammation), cirrhosis (scarring of the liver), and pancreatitis (inflammation of the pancreas).

But the most dangerous complication, Dr. Brugge says, is gallbladder inflammation called cholecystitis. It results from a gallstone getting stuck in the gallbladder, which becomes infected and causes searing pain. “It’s a pretty dramatic illness,” he says. “The gallbladder can rupture or leak infected bile, and the infection can spread through the body. It can be fatal.”

New evidence suggests gallstones may also raise the risk of developing cancers of the liver, bile duct, and pancreas. A study published online June 17, 2022, by the

British Journal of Cancer

tracked more than 115,000 women and nearly 50,000 men for up to 30 years, asking about their history of gallstones at the study’s start and every other year afterward. Compared with people without gallstones, those who got them were 60% more likely to develop liver cancer, more than four times as likely to develop bile duct cancer, and 13% more likely to develop pancreatic cancer.

Gallbladder cancer itself is relatively rare, diagnosed in about 12,200 Americans each year. “It’s very deadly, but not very common,” Dr. Brugge says.

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