Prescription abbreviations
What TDS means
on a prescription.
TDS on a prescription means three times a day. It is short for the Latin ter die sumendum and is the form used on prescriptions in India and the UK. American prescriptions write it TID, from ter in die.
TDS
three times a day
ter die sumendum, Latin for “three times a day”
Also written t.d.s., TID, t.i.d.
TDS and TID
They mean the same: TDS is the Indian and UK form, TID the American one.
Not to be confused with TIW
TIW, sometimes written for three times a week, is easily misread as three times a day. The safety group ISMP lists it as error-prone.
What TDS doesn’t say
It says how often, not how much or exactly when. The amount, the time of day and anything about food come from the rest of the prescription, the label or the pharmacist.
Setting it up in AlongWell
Type it as the prescription has it, such as “Metformin 500 TDS after food”, and AlongWell reads TDS as three times a day and sets the reminders from your family’s meal times. You check the times before saving.
Questions
What does TDS mean on a prescription?
Three times a day. TDS is short for the Latin ter die sumendum.
Is TDS the same as TID?
Yes. TDS is the form used in India and the UK, and TID in the US. Both mean three times a day.
Does TDS mean every 8 hours?
TDS means three times a day. Whether the doses should be 8 hours apart or spread through the waking day depends on the medicine, so follow the prescription or ask your pharmacist.
Sources
- Shetty Y and others, Indian Journal of Medical Research, 2024, read 28 October 2026
- College of Optometrists (UK): pharmacy and drug terms, read 28 October 2026
- MedlinePlus: Some common abbreviations, read 28 October 2026
- ISMP Consumer Medication Safety: Learn to read a prescription, read 28 October 2026
- ISMP List of Error-Prone Abbreviations, Symbols, and Dose Designations (2024), read 28 October 2026
- Partial list of prescription abbreviations (mn.gov), read 28 October 2026
This page explains what an abbreviation means. It doesn’t say how much to take or when: follow what the doctor wrote, and ask your pharmacist if any part of a prescription is unclear.
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