Terms used in prescription writing

The Cambridge medical library has every issue of The Lancet since 5 October, 1823 (the first issue). Glancing through some nineteenth century case histories I frequently found myself stuck. The physicians concerned would usually include their prescriptions, but as I could not read them I could not understand what treatments were being inflicted on the poor patients. I am grateful to Olwen Imrie, retired dispenser for providing the information contained on this page, and to Wendy Roberts, Medical Librarian at the University of Cambridge School of Clinical Medicine. Additional information from Hale-White's Materia Medica Pharmacy and Therapeutics, 29th ed. 1952.

The Structure of a Prescription

Each prescription will have
a Superscription (R., meaning Recipe "Take"),
an Inscription (the list of ingredients),
a Subscription (directions to the dispenser),
a Signature (directions to the patient), and
the intials of the prescribing doctor.

A medicine may have four parts:
the Basis (principal active ingredient),
the Adjuvant (which assists its action),
the Corrigent (which correct its operation), and
the Constituent (vehicle or excipient which imparts an agreeable form).
Not every medicine may have a corrigent or constituent.

The following prescription is for Pilula Colocynthidis & Hyoscyami which is a hydrogogue cathartic (powerful purgative). This medicine was used only once to purge the gut and is not for regular use. It is extremely irritant to the gut and is contraindicated in patients for which transit of the medicine may be delayed. This medicine would never be used today, but was in regular use up until the late 1950's.

colocynthis gr.
aloes gr.ii.
scammonii gr.ii.
hyoscami gr.
saponis duri q.s.
syrupi glucosi liquidi q.s.
- Ft. pil.

Sum. stat.
Sig. "To be taken immediately."

translates as
Take (superscription)
1 grain of colocynth (basis. Dried pulp of Citrullus colocynthis)
2 grains of aloes (adjuvant)
2 grains of scammony (adjuvant. Gum resin from the root of Convovulus scammonia.)
1 grain of hyoscyamus (corrigent)
sufficient hard soap (constituent. Formed from the action of caustic soda on olive oil.)
sufficient glucose syrup (constituent)
- form into a pill.

Let it be taken immediately. (subscription)
On the label, write, "To be taken immediately." (signature)

A.B.C. (doctor's initials)

Weights (Apothecaries)

Granumgr.grain64.8 mg
Scrupulusscruplescruple (20 grains)1.30 g
Drachmadram, dr.dram (3 scruples)3.89 g
Unciaounce, oz.ounce (8 drams)31.1 g
Libralb.pound (12 ounces)373 g
Granum dimidium
Grani dimidium
gr.ss., gr.½half a grain32.4 mg
Granum cum semissegr.iss.grain and a half97.2 mg
Quarta pars grani
Grani quadrans
gr.¼quarter of a grain16.2 mg


Minimumminimminim0.0592 ml (British Imperial)0.0616 ml (US)
Drachma fluidafl.dram, fl.dr.fluid dram3.55 ml (60 fluid minims)3.70 ml (60 fluid minims)
Uncia fluidafl.ounce, fl.oz.fluid ounce28.4 ml (8 fluid drams)29.6 ml (8 fluid drams)
OctariusO.pint568 ml (20 fluid ounces)473 ml (16 fluid ounces)
CongiusCong., C.gallon4550 ml (2 pints)3790 ml (2 pints)

Domestic measures

Cochleare parvum/minimumcoch. parv./min.teaspoon (1 fl. dr.)
Cochleare modicum/mediumcoch. mod./med.dessertspoon (2 fl. dr.)
Cochleare amplum/magnumcoch. ampl./mag.tablespoon (3 fl. dr.)
Cyathus vinarius/vinosuscyath.vin.wineglassful (2-3 oz.)
Cyathus magnuscyath.mag.tumblerful (10 oz.)
Poculumteacupful (5-6 o.z)
Pugillusa pinch
Pollexan inch

Instructions to dispenser

Reciperecipe, Rx, R.take
Mittendusto be sent
Habeatlet him have
Fiat/FiantFt.let it be made
Ampullaamp.an ampoule (containing liquid for injection)
Balneumbaln.a bath
Bolusa bolus (originally a large pill, later = a confection)
Capsulacaps.a capsule
Capsula amylaceaa cachet (medicine coated in a rice-flour paste)
Capsula gelatinaa gelatine capsule
Cataplasmacatapl.a poultice
Chartaa paper/a powder
Clysteran enema
Collyriumcollyr.an eye-wash
Collutoriumcollut.a mouth wash
Confectioconfect.a confection (medicine prepared with sugar, syrup or honey)
Conservaa conserve (medicine prepared with sugar or syrup = a confection)
Cremorcrem.a cream
Electuariumelec.an electuary (medicine prepared with sugar, syrup or honey = a confection)
Emulsioemuls.an emulsion
Emplastrumempl.a plaster
Enemaenem.an enema
Essentiaan essence (solution of volatile oil in rectified spirit, usually 1 part into 5)
Extractuman extract (soluble matter in animal or vegetable tissue extracted with water or alcohol then evaporated)
Fomentaa foment (flannel wrung out in hot water to which a drug may or may not have been added)
Gargarismagarg.a gargle
Haustushaust.a draught
Inhalatioinhal.an inhalation
Injectioinj.an injection
Insufflatioinsuf.an insufflation
Lamellaa lamella (small thin disc made with gelatin and glycerin for dropping into the eye)
Linimentumlin.a liniment (liquid or semi-liquid for applying on the skin for relieving pain)
Lotiolot.a lotion
Massamass.a mass
Melmedicine mixed with honey.
Misturamist.a mixture
Mucilagoa mucilage (viscid solution of gum in water, used for suspending insoluble medicines)
Nebulaneb.a spray
Oculentaan ointment for the eye
Oblatuma cachet
Pastapast.a paste
Perlaa perle (small gelatin capsule)
Pessuspess.a pessary
Pigmentapig.a paint (medicine in a liquid preparation to be applied to the skin by brush)
Pilulapil.a pill
Pulvispulv.a powder
Suppositoriumsuppos.a suppository
Syrupusa syrup
Trochiscustroch.a lozenge (medicated candy)
Unguentumung.an ointment
Vinavin.a wine (weak tincture, the drug being extracted by sherry)
Anaaa.of each
Adto, up to
Quantum sufficiat
Quantum satis
Lege artisleg.art.in the proper way
Secundum artemsec.art.in the proper way
Ad libitumad lib.at pleasure
SigneturS., Sig.let it be labelled
SignaS., Sig.label
DaturD.let it be given

Instructions to Patient

SumatSum.let him take
Sumaturlet it be taken
CapiatCap.let him take
Capiaturlet it be taken
let it be applied
Ex aquaex.aq.in water
More dicto
Modo dicto
m.d.as directed
Post, ante, inter, cibos, cibumafter, before, between, meals
Cum cibo/cibiswith meals
Manein the morning
Nocteat night
Vesperein the evening
Meridieat mid-day
Hora somni
Hora decubitus
at bedtime
Hac nocteto-night
Omni die
Omni in die
Quotidie in dies
o.d.every day
Omni maneo.m.every morning
Omni nocteo.n.every night
Omni die secundaevery second day
Semel dieonce a day
Bis dieb.d.twice a day
Bis in dieb.i.d.twice a day
Bis die sumendusb.d.s.twice a day
Ter in diet.i.d.thrice a day
Ter die sumendust.d.s.thrice a day
Quater in dieq.i.d.four times a day
Quater die sumendusq.d.s.four times a day
Saepe in dieoften during the day
Omni horaevery hour
Omni quadrante horaeEvery quarter-hour
Omni semihoraevery half-hour
Omni hora secundaevery two hours
Omni hora tertiaevery three hours
Quattuor quaque hora (sumendo)q.q.h.every four hours
Sexta quaque hora (sumendo)every six hours
Pro re natap.r.n.when required
Subinde, frequenterfrequently
Si opus sits.o.s.when necessary
Ubi dolor urgeatwhen the pain is violent
Febri adstantewhen the fever is on

Manner of Administration

Phiala prius agitatap.p.a.the bottle being previously shaken
Ex cyatho aquaein a glass of water
Donec alvus dejecerituntil the bowels have been moved
Alvo adstricta/laxatathe bowels being confined/loose
Donec sudor prodeatuntil sweat is produced
Per fistulam vitreamthrough a glass tube
Donec evanescant symptomatauntil the symptoms disappear
In aurem (oculum, &c.) instillarito be dropped into the ear (eye, etc.)
Injiciaturto be injected
Pars affecta fricetur linimento (unguento, &c.)the affected part to be rubbed with the liniment (ointment, etc.)
Applicatur loco affectoto be applied to the affected part
Usque ad vesicationemto be applied until vesication is produced

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This page last updated 27 Aug 1999.
Counter running since 16 May 1999.

Conversions and explanations of the more obscure terms are taken from the Merriam-Webster Dictionary.

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