| Abbreviation | Meaning | Abbreviation | Meaning | |
| a.c. | before meals | o.d. | right eye | |
| a.d. | right ear | o.s. | left eye | |
| a.s. | left ear | o.u. | both eyes | |
| a.u. | both ears | p.c. | after meals | |
| ad lib. | as much as desired | PO | orally | |
| amp. | ampule | p.r.n. | when required | |
| aq. | water | q. | every | |
| b.i.d. | twice daily | q4h, etc. | every 4 hours | |
| c. | with | q.i.d. | four times daily | |
| cap. | capsule | q.o.d. | every other day | |
| cc | cubic centimeter | q.s. or q.s. ad | quantity sufficient to make | |
| disp. | dispense | Rx | take | |
| g or gm | gram | S., or Sig. | Indicates directions to be given on the label of a prescription | |
| gtt(s) | drop(s) | s.i.d. | once a day | |
| h. | hour | stat | immediately | |
| h.s. | at bedtime | Subcut, SC | subcutaneous | |
| IM | intramuscular | SubQ, SQ | subcutaneous | |
| IP | intraperitoneal | susp. | suspension | |
| IV | intravenous | tab | tablet | |
| lb | pound | Tbsp. | tablespoon (15 ml) | |
| m2 | meters squared | tsp. | teaspoon (5 ml) | |
| mg | milligrams | t.i.d. | three times daily | |
| ml | milliliter | Ut dict. | as directed |