What does GTT mean on a prescription?
GTT means drop, and GTTS means drops.
What it stands for
GTT comes from the Latin gutta, meaning a drop. It tells you the dose form: liquid measured in drops rather than tablets or millilitres.
How it looks on a real label
| Sig code | Label directions |
|---|---|
2 gtts ou bid | Instill 2 drops in both eyes twice daily |
1 gtt ad tid | Instill 1 drop in right ear three times daily |
2 gtts os qid prn itching | Instill 2 drops in left eye four times daily as needed for itching |
GTT is almost always paired with a site code saying where the drops go: OU, OD or OS for the eyes, AU, AD or AS for the ears. A drop sig without a site is incomplete and a pharmacist will usually query it.
The verb on the label is normally "instill" rather than "take", which is why these read differently from an oral sig.
Eye and ear preparations are not interchangeable. An ear drop is not sterile to the standard an eye needs, so a product labelled otic must not go in an eye even though both are measured in drops.
Related codes
| Code | Meaning |
|---|---|
OU, OD, OS | both eyes, right eye, left eye |
AU | in both ears |
ML | milliliter |
PO BID | by mouth twice daily |
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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.