What does PO QID mean on a prescription?
PO QID means take the medication by mouth four times daily.
What it stands for
PO QID comes from the Latin quater in die, meaning four times a day. It tells you the frequency: four doses across the waking day.
How it looks on a real label
| Sig code | Label directions |
|---|---|
1 tab po qid | Take 1 tablet by mouth four times daily |
2 tabs po qid pc | Take 2 tablets by mouth four times daily after meals |
1 cap po qid ac | Take 1 capsule by mouth four times daily before meals |
QID and QD are one letter apart and mean four times a day versus once a day. Handwritten, that is a fourfold difference in dose, which is exactly why ISMP lists QD as error-prone and many pharmacies now write "daily" in full.
PO QID is not the same as Q6H
QID means four times a day, usually spread across waking hours: with meals and at bedtime. Nobody sets an alarm for it.
Q6H means every 6 hours on the clock, which necessarily includes an overnight dose. Four doses either way, but Q6H is evenly spaced and QID is not.
The distinction matters most for antibiotics, where the point is keeping the drug level from dipping between doses.
Related codes
| Code | Meaning |
|---|---|
PO TID | by mouth three times daily |
PO BID | by mouth twice daily |
PO QD | by mouth once daily |
Q4-6H | every 4 to 6 hours |
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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.