Causes of gallstone formation include high cholesterol in bile, high bilirubin or failure of the gallbladder to empty properly, and dietary habits. 1. Excessive cholesterol: If the level of cholesterol in the body is higher than the level that can be dissolved by bile, the excess cholesterol will form crystals in the gallbladder and eventually form stones. 2. High bilirubin: Bilirubin is a product of red blood cell destruction in the body. When there is cirrhosis of the liver, biliary tract infections or certain blood disorders, the production of bilirubin increases and this may lead to the formation of gallstones. 3. The gallbladder cannot empty normally: skipping breakfast or certain chronic diseases of the gallbladder affect the normal emptying of the gallbladder, leading to the accumulation and concentration of bile in the gallbladder, which can also promote the formation of gallstones. 4. Dietary habits: Dietary habits are the main reason for the formation of gallstones. Eating high-calorie food, irregular diet or obesity are more likely to cause gallstones. Patients with gallstones should consult a doctor in time, complete the relevant examinations, make a clear diagnosis, and then take the appropriate treatment program.