Prescription abbreviations
What BD means
on a prescription.
BD on a prescription means twice a day. It comes from the Latin bis in die, “twice a day”, and is the form used on prescriptions in India and the UK. American prescriptions write the same thing as BID.
BD
twice a day
bis in die, Latin for “twice a day”
Also written b.d., BID, b.i.d.
BD and BID
They mean the same. BD is the form used on Indian and UK prescriptions, BID on American ones. Some references give the Latin as bis die rather than bis in die; either way it means twice a day.
Not to be confused with BIW
BIW, sometimes written for twice a week, is easily misread as twice a day. The safety group ISMP lists it as error-prone.
What BD 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 BD after food”, and AlongWell reads BD as twice a day and sets the two reminders from your family’s meal times. You check the times before saving.
Questions
What does BD mean on a prescription?
Twice a day. BD comes from the Latin bis in die, “twice a day”.
Is BD the same as BID?
Yes. BD is the form used in India and the UK, and BID in the US. Both mean twice a day.
Does BD mean every 12 hours?
BD means twice a day. Whether the two doses should be 12 hours apart or simply morning and evening 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
- MedlinePlus: Abbreviations, part 2, read 28 October 2026
- ISMP List of Error-Prone Abbreviations, Symbols, and Dose Designations (2024), 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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