If you have ever stood at a pharmacy counter staring at the label on a medicine box and felt unsure what it was actually telling you to do, you are far from alone. Prescriptions and medicine labels are written using shorthand and Latin abbreviations that date back centuries. They were never designed to be read by the person taking the medicine. At Lumen, we hear about this confusion constantly, and it is one of the reasons we created a dedicated guide to help Musselburgh residents make sense of what their medication labels are saying.
Common prescription abbreviations explained
| OD | Once daily (from "omni die") |
| BD | Twice a day — once morning, once evening |
| TDS / TID | Three times a day |
| QDS | Four times a day |
| AC | Before meals |
| PC | After meals |
| OM | In the morning |
| ON | At night |
| PRN | When needed / as required |
The most common abbreviation people ask us about is "OD" — which stands for "omni die," meaning once daily. You might also see "BD," which means twice a day, and "TDS" or "TID," which both mean three times a day. "QDS" means four times a day. None of these are explained on the label itself, because pharmacists and prescribers use them as shorthand with each other, and the system has simply never been updated to make them clear for patients. If your label says "take 1 tablet BD," it means take one tablet in the morning and one in the evening.
Timing matters more than many people realise. "AC" on a label means before meals, and "PC" means after meals. "OM" means in the morning and "ON" means at night. Some medicines work better when taken with food because it protects the stomach lining; others are absorbed more effectively on an empty stomach. If your label says to take a tablet with food, that instruction is there for a reason, not just as a suggestion.
One phrase that causes a lot of worry is "take as directed." This usually appears when the prescriber has given verbal instructions in the appointment that are too detailed to fit on the label. If you see "take as directed" and you cannot remember what you were told, it is completely reasonable to call the surgery or the pharmacy and ask them to explain again. You will not be wasting anyone's time. Getting it right matters more than feeling like you should already know.
Storage instructions are another area where small words carry big meaning. "Store below 25°C" means keep it at room temperature and away from direct sunlight or radiators. "Keep refrigerated" means the fridge shelf, not the freezer. "Keep out of reach of children" appears on almost every medicine and is not just legal small print — many medicines look and taste similar to sweets, and accidental ingestion is a real risk in homes with young children.
If a label says "complete the course," this is especially important for antibiotics. Stopping early, even when you feel better, can allow the infection to come back stronger and harder to treat. Antibiotic resistance is a growing public health problem, and finishing the course is one of the most straightforward things any of us can do to help.
At Lumen, we have a free printed and audio version of this guide available at our Musselburgh drop-in sessions and through several local GP surgeries. If you would like a copy for yourself or someone you care for, get in touch with us directly. Understanding your medicine should never feel like a puzzle you have to solve alone.
