You can usually drink water before having an ultrasound. Ultrasonography utilizes the body’s reflection of ultrasound waves to image the reflected waves from tissues in order to observe and diagnose diseases. Because the quality of ultrasound images will be affected by intestinal gas, the degree of filling of the organs and other conditions, so there are certain requirements for drinking water Most ultrasound examinations can be performed with normal water before the examination, such as pelvic ultrasound, cardiac ultrasound, bladder ultrasound, prostate ultrasound and so on. For bladder ultrasound, you also need to drink a lot of water before the examination to ensure that the bladder is full and more conducive to the examination. A small number of ultrasound examinations, such as liver, gallbladder, pancreas and spleen ultrasound, generally require fasting for more than 8 hours, you can drink a small amount of water, but you can not drink too much, to ensure that the gallbladder and bile ducts are filled with bile, to reduce gastrointestinal distension interference, and to improve the accuracy of the examination. Whether you can drink water before the ultrasound examination is recommended to follow the guidance of professional doctors.