What is BD or TDS?

What Do BD and TDS Mean in Medicine?

Ever picked up a prescription and seen abbreviations like BD or TDS on the label? These aren’t random codes—they’re medical shorthand used by doctors and pharmacists to indicate how often you should take your medication.

BD stands for "bis in die," a Latin phrase meaning "twice a day." So if your prescription says "Take 1 tablet BD," it’s telling you to dose in the morning and again in the evening. It’s a common instruction for medications that need consistent levels in your bloodstream, like certain antibiotics or blood pressure drugs.

Similarly, TDS comes from the Latin "ter die sumendum," which translates to "to be taken three times a day." This means you’ll take your dose roughly every eight hours—morning, midday, and night. Medications for pain, acid reflux, or infections often fall into this category.

While these abbreviations are standard in the UK and some Commonwealth countries, they’re gradually being replaced by clearer language like "twice daily" or "three times daily" to reduce confusion. But you’ll still see BD and TDS on prescriptions, especially in handwritten notes or older systems.

It’s important to follow these instructions closely. Taking medication too often can lead to side effects, while skipping doses might reduce its effectiveness. If you’re ever unsure what an instruction means, your pharmacist is your best resource—never guess.

Understanding simple terms like BD and TDS puts you more in control of your health. They’re small abbreviations, but they carry big responsibility when it comes to getting better—and staying better.