For gallbladder ultrasound examination, it is usually necessary to fast for more than 8 hours, that is, do not eat or drink in the morning when you wake up. The gallbladder can effectively store bile at night, and during the process of bile storage the gallbladder is significantly dilated. At this time, if the ultrasound examination is completed, it can effectively show the condition of the gallbladder wall and clarify whether there are other abnormalities in the gallbladder, such as stones or polyps. If the examination is done in the morning after a meal, the gallbladder is in a contracted state, so it is difficult to observe some other lesions in the gallbladder and the thickness of the gallbladder wall, so the examination of the gallbladder needs to be fasted for more than 8-12 hours.