Which abbreviation means not swallowing anything by mouth?

• A. Nothing by mouth
• B. NPO
• C. By mouth
• D. Out Of Building

Answer: (B)

NPO is the medical abbreviation for nothing by mouth. It comes from the Latin nil per os, which means nothing through the mouth. When a patient is NPO, they should not eat or drink anything, including medications, until a clinician says it’s safe to resume. This is important before surgeries or certain medical tests to prevent choking or aspiration.

Other options don’t fit: using a phrase like “Nothing by mouth” is descriptive but not the standard abbreviation; “By mouth” would indicate oral intake is allowed; and “Out Of Building” has no medical meaning.