Department of Anesthesiology & Perioperative Care: School of Medicine: University of California, Irvine

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Fasting Guidelines

One of the things your anesthesiologist will want to know on the day of your surgery is your "NPO" status. NPO is an abbreviation for "Nothing per Os", which in turn is latin for "nothing by mouth". Anesthesiologists require all patients to fast for a specific period before coming for surgery.

The reason this is important is that regardless of the kind of anesthesia you receive, from a local block up to a general, there are many things in the course of surgery and anesthesia that can place you at risk of aspiration (inhaling stomach contents into your lungs). This is obviously something that we work very hard to avoid. One of the best forms of insurance against aspiration is the knowledge that a patient's stomach is empty.

For this reason the following are the current recommendations by the American Society of Anesthesiologists for NPO status (ie., the number of hours a patient must fast—no food or water—before being taken to the operating room):


  • 8 hours for solids
  • 2 hours for clear liquids (up to 8oz prior to arrival)
  • Eat nothing after midnight the night before your surgery
  • If you have special needs (diabetes, among others) consult with the preoperative clinic to see what options may be available.

Children and infants

  • 8 hours for solids
  • 6 hours for infant formula
  • 4 hours for breast milk
  • 2 hours for clear liquids*

*Clear liquids are water, fruit juices without pulp (not orange juice), carbonated beverages, clear tea and black coffee.

Gum, candies, and breath mints are included in the "NPO" guidelines and should not be consumed within the fasting time span.

If you have any questions about these guidelines please ask, or avoid ingesting the food or drink in question. These guidelines are very important and failure to follow them may result in the delay or cancellation of a procedure. Worse yet, failure to follow them may place you at risk of aspiration, pneumonia and worse.