Understanding Prescription Abbreviations

You may have seen letters like hs, q.i.d., or b.i.d. on your prescriptions. These are abbreviations for Latin phrases.

Centuries ago, all prescriptions were written in Latin. Today these abbreviations are only used in the drug's directions.

Your pharmacy will translate your healthcare provider's instructions on the medicine's label. Sometimes, though, a mistake can happen.

Many drugs, like arthritis medication or pain medication, can be dangerous if you take the wrong dose. Knowing how to read prescription abbreviations can protect you from dangerous errors.

This article will discuss the Latin abbreviations healthcare providers use on prescriptions and help you learn how to translate them. It will also discuss steps you can take to protect yourself from prescribing errors.

5 common prescription abbreviations

Verywell / Ellen Lindner

The Origins of "Rx" as an Abbreviation for "Prescription"

Rx is an abbreviation for "prescription." Most people think it comes from the Latin word "recipe," which means "take."

According to another theory, the Rx symbol is based on the Roman deity Jupiter. Jupiter's symbol looked similar to the Rx symbol. The symbol may have been placed on a prescription to invoke Jupiter's blessing.

An Example of Prescription Abbreviations

Here is an example of what a healthcare provider might write on a prescription:

Sig: 1 tab po qid pc & hs

These abbreviations are instructions for taking the medication. The pharmacist will translate them for the medication label. In this case, the instructions will read: "Take one tablet by mouth four times a day, after meals, and at bedtime."

The abbreviations may be written in capital letters or small letters, and may or may not include periods.

Common Latin Rx Terms

Some common Latin prescription abbreviations include:

  • ac (ante cibum) means "before meals"
  • bid (bis in die) means "twice a day"
  • gt (gutta) means "drop"
  • hs (hora somni) means "at bedtime"
  • od (oculus dexter) means "right eye"
  • os (oculus sinister) means "left eye"
  • po (per os) means "by mouth"
  • pc (post cibum) means "after meals"
  • prn (pro re nata) means "as needed"
  • q3h (quaque 3 hora) means "every three hours"
  • qd (quaque die) means "every day"
  • qid (quater in die) means "four times a day"
  • Sig (signa) means "write"
  • tid (ter in die) means "three times a day"

Declining Use of Abbreviations

The Latin terms are still in use, but some healthcare providers are retiring them. It is becoming more common for healthcare providers to write prescription instructions in plain language.

Readable prescriptions can help prevent medication errors. That is why many medical professionals think written instructions should be used instead of hard-to-read abbreviations.

For example, the abbreviation qd, which means "daily," could be mistaken for qid, which means "four times a day." It could also be confused for od, which means "right eye." Simply writing "daily" prevents confusion.

E-prescribing, or electronic prescribing, can also help prevent medication errors. Instructions sent directly to the pharmacy electronically are less prone to human error. If your healthcare provider uses electronic prescribing, you may never see the abbreviations.

E-prescribing improves patient safety in a number of ways:

  • It eliminates hard-to-read prescriptions.
  • It reduces the need for verbal communication, which can lead to mistakes.
  • It can let the healthcare provider know if the patient has a drug allergy.
  • It can alert the healthcare provider to possible drug interactions.
  • The healthcare provider can easily view the patient's medication history.


Healthcare providers sometimes use Latin abbreviations on prescriptions. Understanding these abbreviations can help you avoid a medication error.

Some healthcare providers are moving away from Latin abbreviations and using plain language instead. Written instructions can help prevent medication errors. Electronic prescriptions can also reduce the chance of a mistake.

A Word From Verywell

If you receive a written prescription, make sure you understand the directions. If the directions are unclear or confusing, ask your healthcare provider or pharmacist to explain. Do not take your medication unless you understand the instructions. Take no chances.

If your medication is prescribed electronically, you may not see the instructions until they appear on the label. At that point, it is important to consult your pharmacist if you have questions. It is always a good idea to go over the instructions with your pharmacist. Do your part to avoid medication errors.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Merriam-Webster. Rx.

  2. Voice of America. Take this medicine: the story of the sign 'Rx'.

  3. Pharmacy Times. A technician's guide to pharmacy abbreviations.

  4. Tariq RA, Sharma S. Inappropriate medical abbreviations. In: StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing;

  5. Porterfield A, Engelbert K, Coustasse A. Electronic prescribing: improving the efficiency and accuracy of prescribing in the ambulatory care settingPerspect Health Inf Manag. 2014;11(Spring):1g.

  6. Kannry J. Effect of e-prescribing systems on patient safety. Mt Sinai J Med. 2011;78(6):827-33. doi: 10.1002/msj.20298.

  7. Cleveland Clinic. Prescription medication labels: how to read.

By Carol Eustice
Carol Eustice is a writer covering arthritis and chronic illness, who herself has been diagnosed with both rheumatoid arthritis and osteoarthritis.