What does HS mean on a prescription?
HS means at bedtime.
What it stands for
HS comes from the Latin hora somni, meaning at the hour of sleep. It tells you the timing: the dose is taken at bedtime rather than at a clock time.
How it looks on a real label
| Sig code | Label directions |
|---|---|
1 tab po qd hs | Take 1 tablet by mouth once daily at bedtime |
1 tab po bid hs | Take 1 tablet by mouth twice daily at bedtime |
You will see both HS and QHS. QHS is "every night at bedtime", which is the same instruction for a once-daily medication. In practice they are used interchangeably on a label.
Bedtime dosing is not arbitrary. Some medications are dosed at night because they cause drowsiness, and others because the process they act on happens overnight.
Related codes
| Code | Meaning |
|---|---|
QAM | every morning |
AC | before meals |
PC | after meals |
PO QD | by mouth once daily |
Translate any sig code free
Paste any sig code into the free sig code translator and get the plain-English label directions instantly. No account needed.
You can also browse the full sig code list, grouped by frequency, route, timing and form.
If you are studying for the PTCB exam or starting in a pharmacy, PharmSig has quizzes and flashcards that track which codes you keep getting wrong, with a 7-day free trial.
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.