Learn to read your prescription


Famous author Mark Twain wrote, in 1864, that doctors should "discard abbreviations… to avoid the possibility of mistakes." We agree! A prescription for medicine should not be a mystery to understand. Many abbreviations and words in prescriptions come from Latin. We'd like to help by explaining each part of a typical prescription and translating some of the Latin abbreviations into English words.

Download: Learn to read your prescription

Rollover letters A-K to for an explanation of each part of a prescription.

{jumi [*3]}

Common abbreviationLatin words that make up the abbreviationThe meaning on your prescription
ac ante cibum before meals
bid bis in die twice a day
gtt gutta drop (as in 1 drop, 2 drops, and so on)
hs hora somni at bedtime
od* oculus dexter right eye
os oculus sinister left eye
po per os by mouth
pc post cibum after meals
prn pro re nata as needed
qd** quaque die every day, or daily
qid quarter in die 4 times a day
tid ter in die 3 times a day

*Sometimes, od is used to mean "once daily." The word "daily" should be used instead to prevent mistakes.

**The abbreviation qd is considered dangerous. It should not be used because it has been mistaken as qid frequently. This mistake has led to serious harm, since people took once-a-day medicine four times each day.

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