Sig (directions)

How to read it

The American Heritage Dictionary gives Sig. three ways: Latin signa, “mark or label it”; signetur, “let it be marked or labeled”; and, in medicine, signature. The Minnesota Board of Pharmacy lists sig simply as “write on label”. It is the last of the traditional parts of a prescription, after the ℞ and the drugs: a 2012 study of prescriptions in Oman describes it as the part, usually preceded by the sign, where the directions to be written on the dispensed medicine go.

Also searched as: sig, sig meaning, sig medical abbreviation, signa.

The Sig line and the Latin shorthand

The layout was standardised in the nineteenth century, according to the historian Robert Woods, with the final line of the prescription giving the patient’s directions, sometimes in English but commonly in abbreviated Latin. That line is where shorthand such as PO, BID and PRN appears, and it is the line that goes onto the label.