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Understanding your medical notes

Prescription abbreviations explained: what your medication label means

"Take 1 tab PO BD PRN" — prescriptions are written in a shorthand of Latin and clinical codes that few patients are ever taught. This guide decodes the dosing abbreviations, the routes, and the rest of the label, so you know exactly how and when to take each medicine.

Written by Nick Lamb, PhD, medical writer MHRA-registered Class I medical device Methods validated in a peer-reviewed study Last reviewed 13 June 2026

Skip the decoding — get your prescription explained in seconds

Paste your prescription or label (or upload a photo, PDF, or Word file) and Patiently AI explains every instruction in plain English and tells you what each medicine is typically for. Free, no account, and identifying details are removed on your device first.

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What's on a prescription or medication label

Dosing frequency abbreviations

AbbreviationWhat it means
ODOnce a day
BDTwice a day
TDSThree times a day
QDSFour times a day
ON / nocteAt night
OM / manéIn the morning
PRNAs needed (only when required)
statImmediately (a one-off dose now)

Route abbreviations (how to take it)

AbbreviationWhat it means
POBy mouth (swallowed)
SLUnder the tongue (sublingual)
PRBy rectum
SCUnder the skin (injection)
IMInto a muscle (injection)
IVInto a vein
INH / NEBInhaled / nebulised
TOPApplied to the skin (topical)

Seeing the name of a drug you don't recognise? Patiently AI's medication checker identifies medicines mentioned and explains what they're typically used for — or paste the whole prescription in for a plain-English breakdown.

What to check before you take a new medicine

  1. The dose and frequency — exactly how much, and how many times a day.
  2. Any timing instructions — with food, on an empty stomach, before bed.
  3. How long to take it — a fixed course, or ongoing?
  4. What it's for — so you understand why you're taking it.
  5. Anything to avoid — other medicines, alcohol, or activities.

Not sure how to take it?

Patiently AI turns "Amoxicillin 500 mg, 1 cap PO TDS for 7/7" into "Take one 500 mg amoxicillin capsule by mouth three times a day for seven days." Clear, for every line.

Try it with your own prescription → Paste, upload, or photograph your label.

Questions to ask your pharmacist or doctor

Patiently AI generates personalised "Questions for your doctor" automatically — a quick way to cover the essentials before you start a new medicine.

Frequently asked questions

What does PRN mean on a prescription?

PRN is Latin ("pro re nata") for "as needed". You take the medicine only when you need it — for example, a painkiller PRN means take it when you have pain, up to the maximum dose stated. The label should say how much and how often.

What do OD, BD, TDS and QDS mean?

They're Latin dosing frequencies: OD = once a day, BD = twice a day, TDS = three times a day, QDS = four times a day. You may also see ON/nocte (at night) and OM/mané (in the morning). If the timing is unclear, your pharmacist can explain.

What does PO mean on a medication label?

PO ("per os") is Latin for "by mouth" — the medicine is swallowed. Other routes include PR (by rectum), SC (under the skin), IM (into a muscle), IV (into a vein), and INH/NEB (inhaled or nebulised).

What does "stat" mean on a prescription?

"Stat" means immediately — a one-off dose to take straight away. It's often used for the first dose of a new medicine before the regular schedule begins.

Can Patiently AI explain my prescription?

Yes. Paste the prescription or label text — or upload a photo, PDF, or Word file — and Patiently AI explains each instruction in plain English, identifies the medications with what they're typically used for, and suggests questions to ask. It's free, needs no account, and removes identifying details on your device before processing.

Important: This guide is general information to help you read a prescription, not medical advice. Always follow the instructions given by your prescriber and the dispensing label, and check anything you're unsure about with your pharmacist or doctor before taking a medicine. Patiently AI rewrites medical text to make it easier to read; it may oversimplify or miss nuance and does not provide dosing or treatment recommendations.