Obtained by sublimation from gum benzoin, or artificially from various hydrocarbons of the aromatic series. The pure crystals are dissolved in alcohol to make the mother tincture. Benzoic acid has a strong local antiseptic action and a specific irritating effect on the gastric and bronchial mucous membranes. It combines with glycocol in the body to form hippuric acid which is excreted from the urine, to which it gives a characteristic strong-smelling odour. The pulse and respiration are accelerated and then slowed from a direct action on the heart and on the respiratory centre. It causes stitching and burning pains in the joints, especially the knees and big toes, with redness and swelling.
Benzoic acid is useful for rheumatic and gouty conditions expressing themselves in tonsillitis, indigestion, diarrhoea, gouty bronchitis and asthma, arthritic pains and urinary affections.
The tongue is spongy, with deep cracks and spreading ulcerations. The throat symptoms are generally relieved by swallowing, as is also a sensation of a lump in the pit of the throat at though food had lodged there, this is better from eating. Diarrhoea of very watery, frothy, offensive stools, white in colour, like soapsuds, especially in the dentition diarrhoea of children. Dull or hot pain in the back over the kidneys, especially the left. Urine highly coloured (brown or dark red), with exceedingly strong urinous odour (see also nitric acid), which appears while the urine is being passed and remains afterwards and is independent of any sediment. It is useful in kidney and bladder affections when this kind of urine is present and in the dribbling of urine in old men with enlarged prostate, and in the nocturnal incontinence of children. Headaches, especially occipital, coming on in the night or due to change of weather and associated with scanty urine, may require this remedy.
Pains and cracking in the knee-joints and stitching pains in the metatarsal joint of the great toe, pains in the cardiac region, and palpitation in association with or alternating with arthritic pains indicate this drug. With its bronchitis the cough is worse at night and from lying on the right side, and greenish mucus is expectorated.
Externally it is useful in ganglion of the wrist and in bunion of the big toe applied as an ointment (benzoic acid, 1 dr.; ung. cetacei, 1 oz.).
(1) The characteristic odour of the urine is the principal indication, and should be present in any case for which benzoic acid is prescribed.
(2) Symptoms usually appear first on the left side.
(3) The pains suddenly change their locality (kali bich., kali sulph., ledum, puls.), and the ailments their nature, e.g, respiratory difficulty alternates with joint pains or with scanty pale urination.
(4) Patient is much affected by unpleasant sights, dwells upon unpleasant ideas when sleepless, causing much depression.
(5) Periods of sleeplessness alternate with nights of heavy sleep.
(6) It is strikingly valuable in subacute rheumatism, or even rheumatic fever, with the characteristic urine and copious sweat.
Symptoms are worse from movement, from the open air, cold draughts and uncovering at night and from taking wine; lying on right side (bronchitis).
Passage of high-coloured, strong smelling urine, internal and articular pains, eating (sensation. of lump in throat), heat.