What does PO mean on a prescription?
PO means by mouth. The medication is swallowed.
What it stands for
PO comes from the Latin per os, meaning through the mouth. It tells you the route: the medication is swallowed rather than applied, inhaled or injected.
How it looks on a real label
| Sig code | Label directions |
|---|---|
1 tab po qd | Take 1 tablet by mouth once daily |
2 caps po bid | Take 2 capsules by mouth twice daily |
10 ml po tid prn cough | Take 10 milliliters by mouth three times daily as needed for cough |
PO is the most common route code there is, because most medications are taken orally. It answers "how does it get in", and it is almost always paired with a frequency code answering "how often".
PO is not the same as SL. Both go in the mouth, but a PO medication is swallowed and absorbed through the gut, while an SL tablet dissolves under the tongue and absorbs directly. Swallowing an SL tablet can waste the dose.
A sig with no route code at all is usually oral by default, but a label should still spell it out. "Take 1 tablet daily" leaves less room for error than a bare frequency.
Related codes
| Code | Meaning |
|---|---|
SL | under the tongue |
PO BID | by mouth twice daily |
TOP | topically |
PR | rectally |
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You can also browse the full sig code list, grouped by frequency, route, timing and form.
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This page is educational and is not medical advice. Always follow the directions on your own prescription and ask your pharmacist if anything is unclear.