NPO Meaning: Nothing by Mouth Before Surgery
Quick answer
NPO means nothing by mouth: no food and no drink. It comes from the Latin nil per os. Doctors order NPO before surgery and some procedures where you get medicine to put you to sleep. An empty stomach lowers the chance that food or liquid gets into your lungs while you sleep.
Best forPeople getting ready for surgery, those who care for them, and nursing students who see NPO on charts.
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Medical Abbreviations - Essential Clinical Shorthand
The medical abbreviations you actually see on charts, orders, and prescriptions, expanded in plain English. Covers prescription frequency and routes, chart and history shorthand, vital signs, labs and imaging, departments, and provider titles.
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NPO and the orders that go with it
You may see NPO on its own or with a time, and next to the orders below.
| Medical Abbreviations | Pronunciation | Meaning | Listen |
|---|---|---|---|
| NPO | N-P-O | Nothing by mouth: no food or drink | |
| NPO after midnight | N-P-O after midnight | Nothing to eat or drink after 12 at night before surgery | |
| PO | P-O | By mouth | |
| Clear liquids | Drinks you can see through, like water, apple juice, or black coffee or tea with no milk | ||
| Clear liquid diet | Only clear liquids, such as broth, clear juice and water |
Why NPO is ordered: to keep your lungs safe
Medicine for surgery can put you into a deep sleep. While you sleep, food or drink in your stomach could come up and go into your lungs. This is called aspiration. NPO keeps your stomach empty to lower that risk.
| Medical Abbreviations | Pronunciation | Meaning | Listen |
|---|---|---|---|
| Anesthesia | an-es-THEE-zhuh | Medicine that puts you in a deep, sleep-like state for surgery | |
| Aspiration | as-pur-AY-shun | When food, drink or stomach fluid goes into the lungs | |
| Sedation | seh-DAY-shun | Medicine that makes you calm and sleepy for a procedure | |
| Nil per os | nil per OSS | Latin for nothing by mouth |
How long NPO lasts: one hospital's rules
Times differ by hospital and by surgery. Follow the times your own care team gives you. These rows show UCLA Health's rules for adults and teens over 12.
| Medical Abbreviations | Pronunciation | Meaning | Listen |
|---|---|---|---|
| Solid food and dairy | Allowed until 8 hours before your arrival time | ||
| Alcohol | Not within 8 hours of your arrival time | ||
| Clear liquids | Allowed until 2 hours before your arrival time |
Example: what NPO looks like for an 8 a.m. arrival
UCLA Health turns those rules into clock times. If you are due at the hospital at 8 a.m., your last solid food is at midnight and your last clear drink is at 6 a.m. Your own team may set other times.
| Medical Abbreviations | Pronunciation | Meaning | Listen |
|---|---|---|---|
| Midnight | Last solid food or dairy | ||
| 6 a.m. | Last clear liquids, like water or apple juice | ||
| 8 a.m. | Arrive at the hospital |
Frequently asked questions
What does NPO after midnight mean?
It means you stop eating and drinking at 12 at night. Your surgery is the next day. MedlinePlus gives this rule for lung surgery, unless your surgeon says something else.
Can you drink water when you are NPO?
Only if your care team says so. Some hospitals, like UCLA Health, allow clear liquids such as water until 2 hours before you arrive. MedlinePlus says to take the medicines your surgeon told you to take with a small sip of water.
Why are some hospitals moving away from NPO after midnight?
Delays can leave people hungry and thirsty for hours. A 2017 paper in Cureus notes that the ASA, a US group of anesthesia doctors, allows clear liquids up to 2 hours before surgery, which can shorten a long fast.
What does NPO mean on a hospital chart?
On a chart, NPO means the patient gets nothing to eat or drink by mouth until a doctor changes the order.
Is NPO only for surgery?
No. A review from Oregon Health and Science University looks at NPO before procedures done with sedation. Before some bowel surgery, you may also be told to drink only clear liquids the day before.
Where do these facts come from?
We used MedlinePlus, from the US National Library of Medicine. We also used UCLA Health's NPO rules, the OHSU review and a 2017 paper in Cureus.
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