Gallbladder stones 1.5*0.9cm are stones of 1.5cm x 0.9cm size in the gallbladder. Their formation is mostly caused by oversaturation of cholesterol in bile, abnormal nucleation process of cholesterol, abnormal gallbladder function, estrogen and other etiologic factors. 1. Cholesterol oversaturation: oversaturation of cholesterol in bile will lead to the formation of gallbladder stones. 2. Abnormalities in cholesterol nucleation process: the presence of nucleating factors such as glycoproteins, mucins and calcium ions in the bile of patients with gallbladder stones can contribute to nucleation and stone formation. 3. Abnormal gallbladder function: poor contraction of the gallbladder, bile stagnation, resulting in stone formation. 4. Estrogen: estrogen can promote cholesterol supersaturation in bile. It is related to the formation of cholesterol stones, so cholesterol stones are more frequent in women. When the stone reaches 1.5*0.9cm, it is necessary to go to the hospital in time for treatment, so as not to further develop the condition and miss the best time for treatment.