The Full form of AC is Ante Cibum. The term ‘Ante Cibum’ means before a meal. Similarly, OD means the prescribed medicine should be taken “once daily”. If BD is written, medicine should be taken twice daily. Prescribing practitioners or doctors often make use of medical abbreviations – many derived from Latin phrases – when writing out medication orders (or prescriptions). We can think these abbreviations as a kind of medical shorthand. They normally do this in order to provide the individual who is responsible for administering or dispensing the prescribed medication (in most cases a pharmacist or nursing staff) with as much information as possible in a limited space. When we go to a doctor for our treatment, he prescribes so many medicines in the form of tablet, capsule, syrup or any ointment. He also advised us to take the medicine in morning, evening or at night. Sometimes the doctor advises us to take the medicine once or twice a day. When we take medicine before a meal, we may also say it AC and like this, if we take it once daily we may say it OD. So these are the writing patterns of a doctor on a prescription.