How to Fast for an Abdominal Ultrasound

Before an abdominal ultrasound, patients are required to fast for at least eight hours before the procedure, regardless of the reason for the exam. Most people find that fasting for this short amount of time is simple, especially if most of the fasting occurs while sleeping.

Aside from the digestive organs being inactive, fasting allows the stomach to be as small as possible and completely empty to provide optimal conditions for seeing what's inside. Fasting also allows the gall bladder to be seen, which is not possible on a full stomach.

Schedule your ultrasound appointment for early in the morning so the majority of your fasting will occur while you sleep.

Prepare your last meal before fasting to occur between eight and 12 hours before your appointment. Eat a regular size meal so you feel full when finished. Try not to eat salty, fried foods or foods that may cause stomach irritation. Do not drink alcohol at this meal.

Drink water as you would normally. Do not fill up on water or leave yourself dehydrated. Do not drink juice, milk, tea, coffee or anything else but water.

Brush your teeth as normal. Toothpaste, even if swallowed, will not affect an abdominal ultrasound.

Go to sleep. The best activity when fasting is sleeping so you do not eat due to hunger or boredom. If you get hungry during the middle of the night, sip water. If scheduling does not permit you to sleep before your abdominal ultrasound, keep yourself occupied. Do something active like walking or biking. Avoid activities that might trigger you to pick up food, such as watching television, going to a movie or visiting a restaurant.

Sip only water when you wake up in the morning. Do not eat breakfast or take any medications until after your abdominal ultrasound appointment.

Eat a sensible meal after the ultrasound is complete. Eat your first meal after fasting slowly, and do not consume a large portion of food.


If you predict that you will have difficulty going without food for eight hours, talk to your physician. He may be able to provide leverage for you to get an appointment first thing in the morning so most of your fasting hours are overnight.


Always consult your physician about the exact length of time you are required to fast before your procedure and the specific requirements of your fasting.