Table 1. Common Terms and Abbreviations
Term or Phrase  Abbreviation Meaning
ad ad to, up to
ad libitum ad. lib. at pleasure
ana a.a. of each
ante cibos a.c. before meals
aqua aq. water 
bis in die b.i.d. twice a day
collyrium collyr. eye lotion
cum c. with 
cum aqua cum aq. with water
dentur tales doses d.t.d. give such doses
dispensa disp. dispense
et et and
gutta, guttae gtt. drop, drops
hora somni h.s. at bedtime
in vitro in vit. in glass
misce m. mix
non repetatur non. rep. do not repeat
oculus dexter o.d. right eye
oculus sinister o.s. left eye
omni die o.d. daily
omni mane o.m. every morning
omni nocte o.n. every night
per os p.o. by mouth
placebo placebo to please
post cibos p.c. after meals
pro re nata p.r.n. as the occasion arises
quantum sufficiat q.s. sufficient quantity
quater in die q.i.d. four times a day
recipe Rx take
semis ss _ one-half
sine s,s without
si opus sit s.o.s. if necessary
ter in die t.i.d. three times a day
trochiscus, torchisci troch. lozenge, lozenges
unguentum ungt. ointment
ut dictum ut dict. as directed



 
 
Table 2. Approximate Weight and Measure Equivalents
Liquid Measure
Metric Approximate
Apothecary
Equivalents 
Metric  Approximate
Apothecary
Equivalents 
1000 ml 1 quart 3 ml 45 minims
750 ml 1-1/2 pints 2 ml 30 minims
500 ml 1 pint 1 ml 15 minims
250 ml 8 fluid ounces 0.75 ml 12 minims
200 ml 7 fluid ounces 0.6 ml 10 minims
100 ml 3-1/2 fluid ounces 0.5 ml 8 minims
50 ml 1-3/4 fluid ounces 0.3 ml 5 minims
30 ml 1 fluid ounce 0.25 ml 4 minims
15 ml 4 fluid drams 0.2 ml 3 minims
10 ml 2-1/2 fluid drams 0.1 ml 1-1/2 minims
8 ml 2 fluid drams 0.06 ml 1 minims
5 ml 1-1/4 fluid drams 0.05 ml 3/4 minims
4 ml 1 fluid dram 0.03 ml 1/2 minims
Weight
Weight Approximate
Apothecary
Equivalents 
Metric Approximate
Apothecary
Equivalents 
30 Gm 1 ounce 30 mg 1/2 grain
15 Gm 4 drams 25 mg 3/8 grain
10 Gm 2-1/2 drams 20 mg 1/3 grain
7.5 Gm 2 drams 15 mg 1/4 grain
6 Gm 90 grains 12 mg 1/5 grain
5 Gm 75 grains 10 mg 1/6 grain
4 Gm 60 grains (1 dram) 8 mg 1/8 grain
3 Gm 45 grains 6 mg 1/10 grain
2 Gm 30 grains (1/2 dram) 5 mg 1/12 grain
1.5 Gm 22 grains 4 mg 1/15 grain
1 Gm 15 grains 3 mg 1/20 grain
0.75 Gm  12 grains 2 mg 1/30 grain
0.6 Gm 10 grains 1.5 mg 1/40 grain
0.5 Gm 7-1/2 grains 1.2 mg 1/50 grain
0.4 Gm 6 grains 1 mg 1/60 grain
0.3 Gm 5 grains 0.8 mg 1/80 grain
0.25 Gm 4 grains 0.6 mg 1/100 grain
0.2 Gm 3 grains 0.5 mg 1/120 grain
0.15 Gm 2-1/2 grains 0.4 mg 1/150 grain
0.12 Gm 2 grains 0.3 mg 1/200 grain
0.1 Gm 1-1/2 grains 0.25 mg 1/250 grain
75 1-1/4 grains 0.2 mg 1/300 grain
60 mg 1 grain 0.15 mg 1/400 grain
50 mg 3/4 grain 0.12 mg 1/500 grain
40 mg 2/3 grain 0.1 mg 1/600 grain