PO Medical Abbreviation: A Simple Guide

What Does PO Mean?

PO stands for "per os", a Latin phrase. It means by mouth.

Doctors and pharmacists use PO when giving instructions about how to take medicine. If a prescription says “take one tablet PO,” it means you should swallow the tablet through your mouth, not use it in any other way.

You may see PO written on prescription labels, discharge notes, or medication charts in hospitals.

How Is PO Used in Prescriptions?

PO tells you the route of administration, not the dosage amount or frequency.

It simply answers the question: how should you take the medication?

Here’s what it may look like in real use:

• Take 1 capsule PO twice a day
• Administer 5 mL PO every 8 hours
• 1 tablet PO at bedtime

PO instructions usually apply to:

• Tablets
• Capsules
• Liquids
• Lozenges

If your medicine says PO, you should not crush it, mix it, or apply it in any other way unless your doctor gives you specific instructions.

PO vs Other Routes

It helps to understand PO by comparing it with other common medical abbreviations that describe how medicine enters the body:

• IV - intravenous (into a vein)
• IM - intramuscular (into a muscle)
• SC or SubQ - subcutaneous (under the skin)
• SL - sublingual (under the tongue)
• PR - per rectum (into the rectum)
• INH - inhalation (into the lungs)

According to research, PO is the most frequently used route for drug delivery because it is convenient, non-invasive, and easy for patients to manage. It doesn’t require injections or special tools. However, some drugs can’t be taken by mouth due to poor absorption or digestive breakdown.

Why It Matters

The route of administration affects how fast and how well a drug works.

Taking a medicine the wrong way can:

• Reduce its effectiveness
• Cause side effects
• Lead to serious health risks

For example, some tablets meant for IV use can damage your digestive tract if swallowed. Others that are meant to be chewed or dissolved under the tongue won’t work properly if swallowed whole.

Always follow the route exactly as written.