Last modified on January 7th, 2019


Homeopathic remedy Cantharis from A Manual of Homeopathic Therapeutics by Edwin A. Neatby, comprising the characteristic symptoms of homeopathic remedies from clinical indications, published in 1927.

      Cantharides. Tincture made from the dried Spanish fly a beetle. N.O.Coleoptera.


      CANTHARIS is the well-known “Spanish fly,” used as a rubefacient and vesicant or blistering preparation. Its action as a vesicant is slow-ten or twelve hours-but it can be hastened by the application of a hot poultice. An ointment acts more quickly than the plaster.

The active principle of cantharis is an anhydride known as cantharidin (C10H12O1). This is more soluble in alcohol and fatty substances than in water, and for this reason oily substances should not be given as demulcents in poisoning by cantharides. (The stomach should be emptied as quickly as possible and alkalies or kaolin should be administered.)

Formerly it was used as a diuretic and for chronic nephritis, but it has been abandoned as dangerous. It is used as a popular hair wash for alopecia.


      The sphere of action of cantharis is very definite, and the local effects predominate over the general. The pathogenic and therapeutic effects will be considered together.

It is best known for its skin action: it produces redness and burning on the sound akin; on this erythematous base small vesicles form and these coalesce to form a large blister or blisters. There is some evidence from its exertion by the skin with the perspiration, and not only where applied locally. In any case, it is certain that it is used with success in minute doses for acute eczema and erysipelas, in each case wit5h blisters; and for blistering due to sunburn, burns or rhus poisoning. A weak, watery preparation not stronger than I per cent should be applied at the same time as the remedy is given internally.

Burning of the skin before the blisters form is a conspicuous symptom.

Genito-urinary System-The specific effects of cantharis are most marked upon the urinary apparatus, and first upon the kidneys through which the active element is chiefly excreted. Elimination also takes place via the bowel and with the sweat.

The results of this excretion by the kidneys are very constant, varying in intensity with the dose. After small doses increased frequency of micturition and some increase in the quantity of urine occur. After large doses cystitis and acute tubular nephritis are produced, with accompanying albuminuria and tube casts-a condition resembling post-scarlatinal nephritis. In the poisoning the symptoms of both conditions (cystitis and nephritis) are present. The former is evidenced by frequent, almost constant, desire to pass water, with intolerable urging in severe cases, before, during and after micturition. This is accompanied with violent burning and cutting pains in the bladder and urethra, great straining and sometimes strangury-i.e., inability in spite of straining to pass more than a few drops at a time. The urine may contain blood and may be scanty, almost to suppression.

Aching, amounting to severe pain in the loins and extending down towards the hypogastrium, characterizes the nephritis and the urine will contain albumin, possibly blood and tube casts. These affections, occurring “naturally” are seldom so extremely acute as those due to cantharides poisoning, and they are not necessarily or indeed usually present at the same time, commonly having different causes.

Mild or severe, associated or separate, they are conditions for which cantharis is prescribed (in attenuation), with such manifest and rapid benefit that no more striking illustration of the value of Hahnemann’s rule can be so small as not to aggravate the inflammations-from the 3x dilution upwards being commonly used. It has also been prescribed for incontinence of urine ion the day-time in elderly women, but it is more indicated in retention.

Toxicologically, in close connection with the urinary irritation is that of the genital organs. In both sexes sexual excitement is caused with local irritation. In the male, strong erections, even priapism, worse at night, come on, sometimes associated with emissions of bloodstained semen. Sexual desire is violent and imperious, but intercourse is painful or impossible on account of priapism; if accomplished, it dies not relieve rectal and vesical tenesmus. Aching along the spermatic cords and burning feeling in the rectum at the level of the prostate occur during and after sexual intercourse. Inflammation of the the external organs is produced, going on, it is said, even to gangrene. In women, acute vulvitis, also leading to death of tissue, pains in the ovarian regions and itching soreness and burning in the vagina occur; and miscarriage may ensue if the attack poisoning or clinical-occurs during early pregnancy. Menstruation may be premature and profuse.

Clinically, all these genito-urinary conditions are most frequently gonorrhoeal, next septic, or associated with some zymotic or other acute condition and the remedy, at some stage of the malady most often required will be cantharis.

Used by some in substantial doses as an aphrodisiac, and largely for cattle for the same purpose it is used homoeopathically as a sexual sedative, particularly if the excitement is due to local irritation, rather than having a cerebral source. Sexual mania in either sex if associated with the irritative local symptoms described would be benefited by cantharis.

Alimentary Tract.- The symptoms of irritation in the throat, oesophagus, stomach, and upper part of intestinal canal are less significant, being purely physico-chemical local effects, but abdominal flatulent distension and tenderness, with constant rectal tenesmus and burning, the passage of blood and mucus (which however, does not bring relief to the urging) or of pure blood may be regarded as specific. Therapeutically, these symptoms would indicate cantharis in proctitis, prostatitis and vesiculitis if acute and if associated with cystitis and urethritis. It is less likely to be called for in dysentery, though the totality of the symptoms may require this remedy. Pelvic peritonitis, ovaritis, associated with the acute symptoms described, would probably call for it. It has been used in enteric fever with tympanites, burning abdominal pain and dysuria. Respiratory System.- The voice becomes hoarse and weak and there is burning in the larynx.

The pleura is another of the serous membranes which may come under the irritating influence of cantharis quite apart from the possible effect of a local blister. The right side seems to be chiefly affected; stitching shooting pains are common, effusion into the pleural cavity, with shortness of breath and inability to take deep breaths on account of the pain are the chief features diagnostic both of the poison and the remedy. The drug resembles both bryonia and kali carb., but is indicated in more acute cases and particularly if due to some septic focus in the genito-urinary sphere. (compare crotalus and sanguinaria)

Pneumonia of a septic type, with great burning in the chest, rapid prostration stinking breath and sputum, face Hippocratic suggesting gangrene, may clear up under cantharis.

Mind.- Toxicologically any mental symptoms present seem to be secondary to local conditions, but they may possibly be due to some analogous irritation of the membranes of the brain. A burning and bursting headache, with stabbing pain and flushed face, is likely to be present. The symptoms somewhat resemble hydrophobia. There are anxiety, restlessness and rage and sometimes even furious delirium. It is chiefly paroxysms of convulsions and rage, with tearing of clothing and biting worse from the slightest touch, from a bright light and from looking at water which recall the hydrophobic state and have suggested the use of cantharis in this disease. The eyes protrude and have a fixed stare. It is uncertain to what extent it has been actually useful.

Similar delirium and rage in delirium tremens, with shouting or singing of obscene or disgusting subjects, might easily be suggestive of phosphorus, hyoscyamus or cantharis, but the last- named is not very likely to be thought of unless there were cutaneous or urinary associated symptoms-the same may be said of cantharis and hydrophobia. In milder mental aberrations the patient wanders on about his business and about dead people. He may simply be contradictory or insolent. Violent maniacal symptoms may be succeeded by sudden loss of consciousness.

Generalities.- General symptoms are much less conspicuous than local ones, but serious adynamia with quick and weak pulse and slightly raised temperature a tendency to faintness a general stiff feeling and sensitiveness or burning of the whole surface will rank as general, as also may convulsions.

External coldness and shuddering with inward burning especially after acute illnesses such as diphtheria may be helped by cantharis. Paraplegia and incontinence of urine, suggestive of some spinal lesion, are reported as having been due to the poison. Therapeutic results in idiopathic paraplegia cases have been temporarily helped as regards incontinence and the drug should be thought of in post-diphtherial paralysis, especially as it has caused a throat condition recalling diphtheria also.

Yellow fever, with suppression of urine, haemorrhage from the bowel, stomach, &c and cold sweat of face and body, has been treated by cantharis.


      (1) Aversion from drink, food and tobacco may exist.

(2) General burning and sensitiveness of surface.

(3) Burning prominent throughout the case.

(4) weakness, faintness, feeble pulse, with external coldness and shuddering and internal burning-after acute illness.

(5) Acute cystitis and nephritis.

(6) Acute dermatitis with vesication and burning.

(7) Acute sexual excitement and local inflammations in both sexes.

(8) Delirium resembling acute alcoholic poisoning or hydrophobia.

(9) Paroxysms of rage and convulsions.

(10) Pleurisy with effusion: pneumonia, tending to gangrene.

(11) Proctitis and prostatitis.

(12) Pelvic peritonitis, gonorrhoeal or septic.

(13) Erysipelas with vesication; dermatitis with burning of surface, from scalds, sun, &c., especially of the face.

(14) Severity and suddenness of onset with rapid progress.

(15) thirst, from dryness of throat, but fear of drinking lest it cause spasm of dyspnoea.


      From drinking even a little water (cystitis), from coffee (general), and from movement and touch.


      In the morning in bed; at night (mental symptoms): at night, all pains except abdominal: from eructations and passing flatus: from warmth.

About the author

Edwin Awdas Neatby

Edwin Awdas Neatby 1858 – 1933 MD was an orthodox physician who converted to homeopathy to become a physician at the London Homeopathic Hospital, Consulting Physician at the Buchanan Homeopathic Hospital St. Leonard’s on Sea, Consulting Surgeon at the Leaf Hospital Eastbourne, President of the British Homeopathic Society.

Edwin Awdas Neatby founded the Missionary School of Homeopathy and the London Homeopathic Hospital in 1903, and run by the British Homeopathic Association. He died in East Grinstead, Sussex, on the 1st December 1933. Edwin Awdas Neatby wrote The place of operation in the treatment of uterine fibroids, Modern developments in medicine, Pleural effusions in children, Manual of Homoeo Therapeutics,

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