Last Updated on December 2, 2025 by Bilal Hasdemir

Gallstones are a common digestive problem that form when substances in bile—especially cholesterol or bilirubin—become imbalanced and crystallize. Most stones develop in the gallbladder, though some can form or migrate into the bile ducts and cause additional issues. The ultimate guide to what causes gallstones. We explore the critical roles of diet, genetics, and lifestyle in their formation.

For many people, gallstones result from a combination of factors, including cholesterol supersaturation of bile and a relative bile salt deficiency. These changes can lead to painful attacks and, in some cases, serious complications that require treatment.

Key Takeaways

1. Gallstones are common and can affect millions of people worldwide; risk rises with age and in certain groups.
2. Multiple causes contribute to gallstone formation—cholesterol imbalance and low bile salts are primary drivers for the common cholesterol type.
3. Symptoms range from none to severe upper right abdominal pain; untreated stones can lead to infection or pancreatitis.
4. Understanding what causes gallstones helps guide prevention, diagnosis, and treatment choices.
5. Read on to learn who is at higher risk, how stones form, when to seek care, and what treatment options exist.

Medical disclaimer: This article provides general information and is not medical advice. If you have severe abdominal pain, fever, or jaundice, seek immediate medical attention.

Understanding Gallstones: An Overview

Gallstones are hard deposits that form in the gallbladder, the small organ beneath the liver that stores bile for digestion. Many people with gallstones have no symptoms, but when stones block the bile ducts or inflame the gallbladder they can cause pain and other problems (cholelithiasis).

Definition and Types of Gallstones

There are two main types of gallstones, classified by composition and clinical implications:

• Cholesterol gallstones: Usually yellowish and composed mainly of crystallized cholesterol; they are the most common type and are often linked to obesity, rapid weight change, and cholesterol metabolism.
• Pigment gallstones: Darker and smaller, formed from excess bilirubin; they are associated with conditions that increase bilirubin (for example, hemolytic anemias or biliary infections).

Identifying the stone type helps clinicians choose the best approach—see the Anatomy and Causes sections for how bile composition and gallbladder function affect stone formation.

Prevalence and Demographics

Gallstones are common across the population but vary by age, sex, and ethnicity. They become more frequent with age and are more likely in women, especially during childbearing years due to hormonal effects on bile. Certain groups (for example, some Native American and Hispanic populations) show higher rates.

Example case: a 55-year-old woman with intermittent upper right abdominal pain after fatty meals may have symptomatic gallstones—diagnosis is usually with ultrasound and clinical correlation.

Understanding types, who is at higher risk, and how common gallstones are helps guide prevention and individualized treatment plans.

The Anatomy and Function of the Gallbladder

The gallbladder is a small, pear-shaped organ tucked under the liver that stores and concentrates bile, a digestive fluid made by the liver. Bile helps the body break down fats and absorb fat-soluble vitamins in the small intestine.

Normal Gallbladder Function

When you eat, especially fatty foods, the gallbladder contracts and sends concentrated bile through the cystic duct into the common bile duct and then into the small intestine. This coordinated flow from hepatic ducts → common hepatic duct → cystic duct → common bile duct ensures bile reaches the intestine to aid digestion.

The gallbladder’s ability to concentrate bile and release it on demand is important; if the organ does not empty well (stasis) or bile composition is altered, people can develop stones or other gallbladder problems.

Bile Composition and Production

Bile is a complex mixture that includes bile salts, cholesterol, phospholipids, bilirubin, and electrolytes. The liver continuously produces bile—estimates vary, but on average it produces several hundred milliliters to about one liter per day—which the gallbladder concentrates and stores until needed.

Bile Composition:

• Bile salts (key for digesting fats)
• Cholesterol (can crystallize if oversupplied)
• Phospholipids (help solubilize cholesterol)
• Bilirubin (a breakdown product of red blood cells)
• Other electrolytes and organic molecules

The right balance of these components keeps bile fluid and non‑lithogenic; disruptions in bile composition or gallbladder motility increase the risk of gallbladder disease and gallstones.

What Causes Gallstones: The Primary Factors

Gallstones form when changes in bile chemistry or gallbladder function allow crystals to develop and grow into stones. The two core processes are cholesterol supersaturation (too much cholesterol relative to bile salts) and a deficiency or loss of bile salts — both make bile more likely to crystallize into gallstones.

Cholesterol Imbalance

When bile becomes supersaturated with cholesterol, cholesterol molecules can precipitate and nucleate into crystals that grow into cholesterol gallstones. Common contributors include:

• Diet and metabolism: diets high in saturated fat or excess calories and metabolic conditions that alter cholesterol handling.
• Obesity and weight changes: excess body fat — especially abdominal obesity — raises hepatic cholesterol secretion into bile; rapid weight loss can also promote stone formation by altering bile composition and gallbladder emptying.
• Medical conditions: diabetes and high triglycerides can shift lipid metabolism and increase gallstone risk.

Clinical example: an overweight patient with high triglycerides may have bile that carries more cholesterol, increasing the chance of cholesterol gallstones.

Bile Salt Deficiency

Bile salts keep cholesterol dissolved in bile. A reduction in bile salts—due to decreased production (liver disease), impaired enterohepatic recycling, or intestinal loss—reduces cholesterol solubility and raises gallstone risk. Causes include:

• Liver disorders that impair bile production
• Intestinal diseases (e.g., Crohn’s disease) or surgical resections causing bile salt malabsorption
• Some medications that alter bile composition or enterohepatic circulation

Understanding these primary mechanisms — cholesterol oversaturation and bile salt deficiency — explains why prevention often focuses on diet, weight management, and treating underlying liver or intestinal conditions. (See Medical Conditions and Prevention sections for practical steps.)

The Biochemical Process of Gallstone Formation

Gallstone formation follows a stepwise biochemical process in bile that explains why some people develop stones while others do not. The main stages are: supersaturation (too much cholesterol relative to bile salts), nucleation (initial crystal formation), growth/aggregation (crystals join and enlarge), and possible obstruction when stones block ducts or impair gallbladder emptying.

Supersaturation of Bile

Bile — produced by the liver and stored in the gallbladder — contains bile salts, cholesterol, phospholipids, and bilirubin. When cholesterol exceeds the solubilizing capacity of bile salts (supersaturation), cholesterol comes out of solution as microscopic crystals. In plain terms: bile that carries too much cholesterol becomes unstable and starts to form solid particles.

Crystal Formation and Growth

Once crystals form (nucleation), several factors determine whether they grow into clinically important stones. Mucins and certain proteins in bile can promote crystal aggregation, while normal gallbladder emptying helps flush small crystals into the small intestine before they grow. Cholesterol stones typically follow this supersaturation → nucleation → aggregation pathway, whereas pigment stones are more directly linked to excess bilirubin and hemolysis.

Sequence at a glance:

1. Supersaturation: bile contains excess cholesterol relative to bile salts.
2. Nucleation: microscopic cholesterol crystals form.
3. Growth/aggregation: crystals stick together (mucins/proteins promote this).
4. Obstruction: growing stones may block the cystic or common bile duct or impair gallbladder emptying, causing symptoms and complications over time.

If crystals or stones cause symptoms, see the Diagnosis and Treatment sections below to learn which imaging and therapies are used.

Genetic Factors Contributing to Gallstone Development

Genetics contributes to the risk of gallstones: studies suggest that family history and inherited gene variants can change bile composition or gallbladder function, increasing the chance of stone formation. Genetic factors interact with lifestyle and medical risk factors, so heredity raises susceptibility but is not the sole cause.

Hereditary Risk Patterns

Having a first‑degree relative with gallstones is a recognized risk factor and indicates a possible genetic predisposition. Twin and family studies suggest a heritable component to gallstone disease, though environmental and metabolic factors also matter.

Genetic Mutations Affecting Bile Composition

Certain genetic variations influence how the liver secretes cholesterol and bile salts, making bile more lithogenic (stone‑forming). For example, variants in the ABCG8 gene have been associated with higher cholesterol secretion into bile and increased cholesterol gallstone risk.

Genetic FactorEffect on Gallstone Formation
Family history	Signals increased susceptibility; consider earlier counseling or monitoring
Genetic variants (e.g., ABCG8)	Alter bile composition (more cholesterol), making bile more likely to form stones
Hereditary patterns	Interact with diet, weight, and metabolic conditions to raise overall risk

Clinical implication: if you have a family history of gallstones, discuss risk factors (weight, diet, metabolic disease) with your clinician — lifestyle measures can often reduce risk even when genetic predisposition exists. Ongoing research may improve genetic risk prediction and targeted prevention in the future.

Demographic Risk Factors for Gallstones

Some groups have a higher risk of developing gallstones because of age, sex, ethnicity, and family history. Recognizing these patterns helps target prevention and earlier evaluation.

Age and Gender Considerations

Gallstone incidence rises with age, and people over about 40 are more commonly affected. Women are at higher risk than men—especially during childbearing years—because estrogen increases cholesterol secretion into bile and can slow gallbladder emptying. (Studies consistently show higher rates in women, though exact ratios vary by population.)

Ethnic and Racial Predispositions

Rates of gallstone disease differ across ethnic groups. For example, some Native American populations and certain Hispanic groups have higher prevalence than non‑Hispanic whites. These differences reflect a mix of genetic predisposition and environmental factors.

Family History Impact

A family history of gallstones is an important risk factor and suggests inherited susceptibility combined with shared lifestyle influences. If you have a first‑degree relative with gallstones, discuss preventive steps—such as healthy weight management and dietary choices—with your clinician.

Quick guide — High‑risk groups: older adults (≥40), women (especially with estrogen exposure), certain ethnicities (e.g., some Native American and Hispanic populations), and people with a positive family history. If you fall into these categories and have symptoms, consider medical evaluation.

Lifestyle Factors in Gallstone Pathogenesis

Lifestyle choices strongly influence gallstone risk. Diet, body weight, and physical activity change bile composition and gallbladder function, so modifying these factors can reduce the chance of gallbladder disease and symptomatic gallstones.

Dietary Influences

Your diet affects bile and cholesterol levels. Diets high in saturated fat, excess calories, and refined carbohydrates raise the risk, while a fiber-rich diet supports healthier bile and regular bowel habits.

Practical dietary tips to lower risk:

• Favor whole foods: plenty of fruits, vegetables, and whole grains to increase fiber intake.
• Choose healthy fats (olive oil, nuts, avocados) instead of saturated fats from fried and fatty processed foods.
• Limit refined carbs and added sugars; aim for balanced meals with lean protein and fiber.

Weight and Obesity Connections

Excess body weight—especially central (abdominal) fat—boosts liver cholesterol output, making bile more likely to form cholesterol gallstones. Conversely, very rapid weight loss (extreme low‑calorie diets or some post‑bariatric periods) can also increase stone risk because of changes in bile composition and slower gallbladder emptying.

Recommendations:

• Aim for gradual, sustainable weight loss (about 1–2 pounds per week) if overweight.
• Work with a clinician for supervised plans after bariatric surgery; some patients receive short-term medical prevention.

Physical Activity Levels

Regular exercise improves insulin sensitivity, supports healthy weight, and reduces gallstone risk. Follow general public health guidance—about 150 minutes of moderate activity or 75 minutes of vigorous activity per week, plus strength training—and tailor activity to your ability.

Warning: avoid crash diets and extreme fasting, which can paradoxically raise gallstone formation risk. If you have risk factors or are planning rapid weight loss, discuss preventive strategies with your healthcare provider.

Adopting balanced diet habits, sensible weight goals, and regular exercise is one of the most effective, low‑risk ways to lower your chance of gallstones and improve overall health.

Medical Conditions Associated with Gallstone Formation

Several medical conditions increase the likelihood that bile composition or gallbladder function will change in ways that favor gallstone formation. Recognizing these links helps clinicians identify higher-risk patients and consider earlier monitoring or prevention strategies.

Metabolic Syndrome and Diabetes

Metabolic syndrome (a constellation of high blood pressure, elevated blood sugar, abnormal lipids, and central obesity) and diabetes are associated with altered lipid metabolism and insulin resistance, which can increase hepatic cholesterol secretion into bile and slow gallbladder emptying. Studies show these metabolic disorders raise the risk of cholesterol gallstones.

Liver and Intestinal Diseases

Liver disorders such as cirrhosis can disrupt bile production and the balance of bile salts and cholesterol, making bile more lithogenic. Intestinal diseases (for example, Crohn’s disease) or surgical removal of portions of the small intestine can cause bile salt malabsorption or loss, reducing the bile’s ability to dissolve cholesterol and increasing stone risk.

Hormonal Disorders

Hormonal changes affect bile and gallbladder motility. Elevated estrogen—seen in pregnancy or with hormone therapy—increases cholesterol secretion into bile and may reduce gallbladder contractility, promoting stone formation. Other endocrine disorders that alter lipid metabolism can similarly influence gallbladder disease risk.

Clinical implications: patients with metabolic syndrome, diabetes, chronic liver disease, Crohn’s disease, or significant hormonal exposures should be counseled about gallstone risk. Monitor symptoms closely and consider earlier imaging (ultrasound) if abdominal pain, jaundice, or signs of infection appear—because gallstones can lead to complications such as cholecystitis, biliary infection, or pancreatitis.

Medications and Treatments That May Cause Gallstones

Certain medications and medical treatments can increase the risk of gallstones by altering bile composition or gallbladder motility. Knowing these associations helps clinicians and patients weigh benefits and consider monitoring or preventive measures.

Hormone Replacement Therapy

Hormone replacement therapy (HRT) and other estrogen exposures (including some contraceptives and pregnancy) are linked to higher gallstone risk because estrogen increases cholesterol secretion into bile and can reduce gallbladder emptying. Discuss HRT risks and benefits with your prescriber, especially if you have additional risk factors for gallbladder disease.

Cholesterol-Lowering Medications

Most statins do not significantly raise gallstone risk and may even reduce cardiovascular risk without large effects on bile. However, certain lipid‑modifying drugs such as fibrates (used to lower triglycerides) have been associated in some studies with an increased risk of cholesterol gallstones by changing bile composition. If you take lipid medications, talk with your clinician about overall risks and alternatives.

Rapid Weight Loss Treatments

Rapid weight loss—whether from very‑low‑calorie diets or the early period after bariatric surgery—raises gallstone risk because changes in bile composition and reduced gallbladder contraction favor stone formation. In patients undergoing bariatric surgery, some providers consider short‑term prophylaxis with ursodeoxycholic acid or close ultrasound monitoring during rapid weight loss phases; discuss options with your surgical team.

Practical guidance: before starting HRT, fibrates, or a rapid weight‑loss program (including surgery), review gallstone risk factors with your provider. In people at high risk, clinicians may recommend monitoring, consider alternative medications, or discuss prophylactic strategies when evidence supports them.

Recognizing Gallstone Symptoms and Complications

Early recognition of gallstone symptoms helps get timely care and avoid serious complications. Some people have no symptoms; others develop intermittent or severe attacks when a stone temporarily or permanently blocks bile flow.

Common Symptoms of Gallstones

Typical signs of symptomatic gallstones include:

• Severe, steady pain in the upper right abdomen (often called biliary colic) that may radiate to the back or right shoulder
• Nausea and vomiting, frequently after fatty meals
• Indigestion, bloating, or excessive gas
• Fever and chills if infection (cholecystitis or cholangitis) develops
• Jaundice (yellowing of the skin and eyes) when a stone blocks the bile duct

Red flags — seek emergency care if you have: severe upper right abdominal pain with fever, persistent vomiting, signs of dehydration, or jaundice. These may indicate obstruction, infection, or pancreatitis and require urgent evaluation.

Potential Complications if Left Untreated

Untreated or obstructing gallstones can cause serious complications:

1. Cholecystitis — inflammation of the gallbladder, usually from an impacted stone; presents with fever, severe localized pain, and elevated inflammatory markers.
2. Pancreatitis — inflammation of the pancreas that can occur if a stone blocks the pancreatic duct; presents with severe mid‑epigastric pain and may require hospitalization.
3. Biliary obstruction — a blocked common bile duct causes jaundice and dark urine; prolonged obstruction can damage the liver.
4. Cholangitis — infection of the bile ducts, a potentially life‑threatening condition characterized by fever, jaundice, and abdominal pain.

Need treatment? Not all gallstones require immediate intervention. Asymptomatic stones are often observed, while symptomatic stones usually need definitive treatment (often cholecystectomy) or urgent care if complications arise. Your clinician decides based on symptoms, imaging, and lab results.

When to see a doctor: make a non‑urgent appointment for recurring biliary colic or milder symptoms; go to the emergency department for red‑flag signs listed above. Prompt diagnosis and management reduce the risk of serious complications.

Diagnostic Approaches for Gallstones

Accurate diagnosis of gallstones and any related complications guides appropriate treatment. Clinicians combine imaging and laboratory tests to confirm stones, assess for obstruction or infection, and decide next steps.

Imaging Techniques

Which test when:

• Ultrasound — first-line for suspected gallstones and cholecystitis. Safe, fast, and excellent at detecting stones within the gallbladder and signs of inflammation.
• MRCP (Magnetic Resonance Cholangiopancreatography) — noninvasive MRI method to visualize the bile ducts when common bile duct stones are suspected or ultrasound is inconclusive.
• CT scan — useful to evaluate complications (e.g., severe inflammation, perforation, pancreatitis) or when other abdominal problems are being considered.
• ERCP (endoscopic retrograde cholangiopancreatography) — both diagnostic and therapeutic: used when a ductal stone is likely and immediate removal or stenting is needed. ERCP carries procedure risks and is typically done by specialists.

Laboratory Tests

Lab tests help detect obstruction, inflammation, or infection and support imaging findings:

• Liver function tests (LFTs) — an obstructive pattern (elevated alkaline phosphatase and conjugated bilirubin) suggests a bile duct blockage.
• Bilirubin — rising conjugated bilirubin often indicates ductal obstruction and correlates with jaundice.
• Complete blood count (CBC) — elevated white blood cells suggest infection or inflammation such as cholecystitis or cholangitis.

Combining imaging (ultrasound first, MRCP/CT as indicated) with targeted labs makes diagnosis reliable and helps determine whether urgent intervention (for blockage, infection, or pancreatitis) is required. If tests suggest duct stones and symptoms are severe, endoscopic retrograde procedures may be performed to remove the obstruction.

Treatment Options for Gallstones

Treatment depends on symptoms, stone type, and complication risk. Many people with asymptomatic stones need no immediate intervention, while symptomatic or complicated gallstones usually require one of several approaches: medical dissolution, endoscopic therapy for ductal stones, or surgery. Choice is individualized based on your health and goals.

Medical Dissolution Therapy

Ursodeoxycholic acid (UDCA) is a medication that can slowly dissolve small, cholesterol‑rich gallstones in patients with a functioning gallbladder. Benefits: non‑surgical and preserves the gallbladder. Limitations: it can take months to years, only works for selected cholesterol stones, and recurrence is possible after stopping treatment.

Surgical Interventions

Removal of the gallbladder (cholecystectomy) is the definitive treatment for recurrent or complicated gallstone disease. Laparoscopic cholecystectomy is the most common approach—minimally invasive, with shorter hospital stay and faster recovery (often days to a couple of weeks) compared with open surgery. Indications for urgent surgery include acute cholecystitis, cholangitis, and gallstone‑related pancreatitis. After gallbladder removal, most people digest fats normally, though a small number may experience transient digestive changes.

Endoscopic and Non‑surgical Ductal Treatments

If stones migrate into the bile ducts, endoscopic retrograde cholangiopancreatography (ERCP) can often remove the obstruction and relieve jaundice or infection; ERCP is both diagnostic and therapeutic and is usually performed before or during definitive gallbladder management when duct stones are present.

Alternative and Complementary Approaches

Dietary changes, weight management, and some complementary remedies are used to manage symptoms but have limited evidence for dissolving established stones. Always discuss alternative therapies with a clinician to avoid interactions with prescribed medications.

Treatment OptionWhen it’s usedBenefitsConsiderations / Risks
UDCA (medical dissolution)	Small cholesterol stones, good surgical candidate? No	Non‑surgical, preserves gallbladder	Slow, not effective for all stones; recurrence possible
Laparoscopic cholecystectomy (surgery)	Recurrent symptoms, complications, or patient preference	Definitive, low recurrence of stones	Surgical risks, typical short recovery; possible temporary digestive changes
ERCP (endoscopic)	Suspected or confirmed common bile duct stones	Removes ductal stones, relieves obstruction	Procedure risks (pancreatitis, bleeding); usually done by specialists

Decision tips: asymptomatic gallstones usually require observation; symptomatic stones typically need surgery or targeted therapy; urgent complications (infection, obstruction, pancreatitis) require immediate intervention. Talk with a gastroenterologist or surgeon about which treatment fits your situation, expected recovery time, and long‑term implications.

Preventing Gallstone Formation

Many gallstones can be prevented with steady, practical lifestyle changes. Focusing on a balanced diet, sensible weight management, and regular activity lowers the chance that bile will become prone to stone formation and supports overall gallbladder health.

Dietary Modifications

What to eat and why: increasing fiber and choosing healthier fats helps maintain balanced bile and regular bowel habits. Fiber-rich foods can reduce cholesterol saturation in bile, while unsaturated fats support better metabolic health.

Practical tips (a sample daily plate):

• Breakfast: oatmeal with berries and a handful of nuts (fiber + healthy fats).
• Lunch: mixed salad with lean protein (chicken, beans), whole‑grain bread or brown rice.
• Dinner: grilled fish or legumes, steamed vegetables, and a small portion of whole grains.

Do’s and Don’ts:

DoDon’t
Eat fruits, vegetables, whole grains, and lean proteins	Rely on high‑fat, fried, or heavily processed foods
Choose healthy fats (olive oil, nuts, avocado)	Eat large amounts of saturated fats and trans fats
Include fiber daily (aim for whole foods)	Use crash diets that cut calories drastically

Lifestyle Changes

Weight and activity: Excess body weight raises gallstone risk by increasing liver cholesterol secretion into bile. Conversely, very rapid weight loss (extreme calorie restriction or some post‑surgery periods) also raises risk. Aim for gradual weight loss—about 1–2 pounds per week—and regular exercise to protect the gallbladder and the rest of the body.

Exercise guidance: aim for at least 150 minutes per week of moderate activity (e.g., brisk walking) or 75 minutes of vigorous activity, plus strength training twice weekly. Tailor plans to your fitness level and medical conditions.

When to discuss prophylaxis: people at very high risk (e.g., rapid planned weight loss, recent bariatric surgery) should talk to their clinician about monitoring or short‑term preventive options. For most people, steady diet improvements, gradual weight loss, and regular activity are effective, low‑risk strategies to reduce gallbladder disease risk.

Conclusion: Understanding and Managing Gallstone Risk

Understanding the causes of gallstones, including genetics, medical conditions, diet, weight, and medications, empowers you to take practical steps to lower your risk and seek timely care.

• Key takeaways: modify diet and weight gradually, stay active, and manage metabolic and liver conditions to reduce bile-related risks for gallstones.
• Treatment is individualized: options range from watchful waiting to medications (for select cholesterol stones) and surgery (laparoscopic cholecystectomy) when symptoms or complications occur.
• When to act: see your primary care clinician if you have recurring upper right abdominal pain, or go to the emergency department for severe pain with fever or jaundice.

Being informed and proactive helps you and your clinician choose the right approach — prevention, timely diagnosis, or treatment — tailored to your health. For more answers, check the FAQ section and consult reliable medical sources or your healthcare provider.

FAQ

References

National Center for Biotechnology Information. Evidence-Based Medical Insight. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9026518/