What Does NPO Mean in Medical Terms?

The Full Meaning

NPO is a Latin abbreviation for nil per os, which translates directly to "nothing by mouth." When a patient is placed on NPO status, they are instructed not to eat, drink, or take anything orally for a defined period.

The abbreviation comes from Latin because medicine historically recorded orders in Latin. While most medical Latin has been replaced with plain English, NPO remains in widespread use across hospitals, surgical centers, and clinics worldwide.

When Is NPO Ordered?

NPO orders are most commonly placed before:

• Surgery or anesthesia — an empty stomach prevents aspiration (inhaling stomach contents) while a patient is unconscious.
• Endoscopy or colonoscopy — a clear GI tract gives the physician a better view.
• Imaging with contrast — some CT and MRI protocols require fasting beforehand.
• Swallowing dysfunction — patients with dysphagia or aspiration risk are kept NPO until a swallowing evaluation is complete.
• Post-operative recovery — bowel rest after abdominal surgery or until return of bowel function.
• Acute illness — nausea, bowel obstruction, or pancreatitis may require temporary NPO status.

NPO Fasting Guidelines

Modern guidelines from the American Society of Anesthesiologists (ASA) and Enhanced Recovery After Surgery (ERAS) protocols have relaxed the traditional "NPO after midnight" rule for most elective procedures:

NPO vs. Clear Liquid Diet

NPO and a clear liquid diet are not the same. A clear liquid diet allows fluids you can see through (water, apple juice, broth, popsicles without fruit pieces). NPO allows nothing at all. If your chart says NPO, do not assume clear liquids are permitted unless your provider explicitly says so.

How NPO Is Documented

In an EHR or on a paper chart, NPO typically appears as a diet order:

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