What Does 1-0-1, BD or TDS Mean?
Prescriptions are written in Latin shorthand nobody explains. Type what is on yours — 1-0-1, TDS AC, OD HS — and get it in plain English, with the times it works out to.
Type it exactly as written — the shorthand, the dashes, the dose. Nothing you type is sent anywhere; it is decoded in your browser.
Enter the shorthand to decode it
Things like 1-0-1, BD, TDS, OD HS or q6h. The full reference is below.
Prescription abbreviations, in full
Every code this tool understands. Most come from Latin, which is why they look like nothing in particular.
How often
ODQD, SID, o.d. | Once a day · from “omni die”On an eye prescription, OD instead means oculus dexter — the right eye. Check whether the medicine is drops before reading this as "once a day". |
BDBID, b.d., b.i.d. | Twice a day · from “bis in die” |
TDSTID, TDS., t.d.s., t.i.d. | Three times a day · from “ter die sumendum” |
QIDQDS, q.i.d., q.d.s. | Four times a day · from “quater in die” |
OM | Every morning · from “omni mane” |
ONnocte | Every night · from “omni nocte” |
HS | At bedtime · from “hora somni” |
MANE | In the morning · from “mane” |
STAT | Immediately — one dose, right now · from “statim” |
SOS | Only if needed · from “si opus sit”No fixed schedule — this is taken only when the symptom appears, up to any limit your doctor set. |
PRN | As needed · from “pro re nata”No fixed schedule — this is taken only when required, up to any limit your doctor set. |
QODalt die, EOD | Every other dayAlternate days, not daily — easy to get wrong on a weekly chart. |
Q4Hq4h, 4 hourly | Every 4 hours |
Q6Hq6h, 6 hourly | Every 6 hours |
Q8Hq8h, 8 hourly | Every 8 hours |
Q12Hq12h, 12 hourly | Every 12 hours |
WEEKLYOW, once weekly | Once a week |
Food timing
AC | Before food · from “ante cibum” |
PC | After food · from “post cibum” |
CC | With food · from “cum cibo” |
BFbefore food, empty stomach, NBM | Before food / on an empty stomach |
AFafter food | After food |
How it goes in
PO | By mouth · from “per os” |
SL | Under the tongue (sublingual) |
IV | Into a vein (intravenous) |
IM | Into a muscle (intramuscular) |
SCSQ | Under the skin (subcutaneous) |
PR | Rectally |
TOPLA | Applied to the skin (topical) |
GTTgtts | Drops · from “guttae” |
OU | Both eyes |
OS | Left eyeEye-prescription notation. If you see OS or OU, then OD on the same line means the right eye, not "once a day". |
INH | Inhaled |
NEB | By nebuliser |
Form & strength
TABT. | Tablet |
CAPC. | Capsule |
SYPSYR | Syrup |
SUSP | Suspension — shake before use |
INJ | Injection |
OINTUNG | Ointment |
SRXR, ER, CR | Slow / extended releaseDo not crush, split or chew a slow-release tablet unless your pharmacist says it is safe. |
MG | Milligrams (strength) |
ML | Millilitres (volume) |
Other notation
Xfor | Duration — e.g. "x 5 days" means for five days |
RX | The prescription itself |
NPO | Nothing by mouth · from “nil per os” |
BBF | Before breakfast |
This decoder translates notation only. It does not tell you what to take, how much, or what to do about a dose you missed. Handwriting is genuinely hard to read and a misread abbreviation is dangerous — if there is any doubt at all, your pharmacist will read the prescription for you, free, in under a minute.
Questions people ask
What does 1-0-1 mean on a prescription?
1-0-1 is positional notation: one dose in the morning, none in the afternoon, one at night. Each position is a time of day and each number is how many to take. So 1-1-1 is one dose three times a day, and 1/2-0-1/2 is half a tablet in the morning and half at night.
What does BD mean on a prescription?
BD means twice a day. It comes from the Latin bis in die. You may also see it written BID. The two doses are usually spaced roughly 12 hours apart, typically morning and night.
What is the difference between OD, BD, TDS and QID?
They are dose frequencies: OD is once a day, BD is twice a day, TDS is three times a day, and QID (also written QDS) is four times a day. All four come from Latin — omni die, bis in die, ter die sumendum and quater in die.
What do AC and PC mean on a prescription?
AC means before food, from the Latin ante cibum — usually about 30 minutes before a meal. PC means after food, from post cibum — usually within 30 minutes of finishing a meal.
Does OD always mean once a day?
No. On an eye prescription, OD means oculus dexter, the right eye, and OS means the left eye. If the medicine is drops and you see OS or OU on the same prescription, read OD as the right eye rather than once a day. If you are unsure, ask your pharmacist.
Is this decoder medical advice?
No. It translates the shorthand into plain English and shows the usual times for that frequency. It does not tell you what to take, how much, or what to do about a missed dose. Always follow the instructions your doctor or pharmacist gave you.