To do ultrasound examination of the gallbladder, it is absolutely not allowed to eat, must be fasting for more than eight hours, the common diseases of the gallbladder are cholecystitis, gallstones, gallbladder polyps, tumors of the gallbladder and so on. If you don’t fast during the examination, because the gallbladder is located behind the pylorus of the stomach, the food in the stomach and the gas produced by the food will hinder the penetration of the ultrasound and make it impossible to see the gallbladder clearly. In addition, during food digestion, the bile in the gallbladder will be partially or completely discharged into the small intestine to assist in food digestion, while the gallbladder will be emptied, resulting in the thickening of the gallbladder wall and the narrowing of the cystic cavity, which will not be able to clearly show the condition of the gallbladder, thus affecting the diagnosis of the gallbladder by ultrasound.