Botanical name: 

The ripe fruit, dried, of Capsicum frutescens, Linné (Nat. Ord. Solanaceae). Tropical America; also cultivated in most tropical countries. Dose, 1 to 2 grains.
Common Names: Cayenne Pepper, Guinea Pepper, Red Pepper, African Chillies, Bird Pepper.

Principal Constituents.—Fixed oil, resin, fats, and the rubefacient and acrid principle capsaicin (C9H14NO2) and a volatile oil, capsicin.
Preparations.—1. Specific Medicine Capsicum. Dose, 1/10 to 2 drops, very largely diluted.
2. Tinctura Capsici, Tincture of Capsicum. Dose, 1/10 to 10 minims.
3. Emplastrum Capsici. Capsicum Plaster (Composed of Oleoresin of Capsicum and Rubber Plaster). Rubefacient.

Specific Indications.—Marked depression and debility, with feeble pulse and repressed secretions; pale membranes with scanty, viscous secretion; tongue dry, harsh, and mouth and salivary secretions suppressed or scanty; atonic dyspepsia of drunkards; alcoholic delirium of the depressive type; congestive chill; colic, with abdominal distention; debility with faulty gastro-intestinal functioning in the aged.

Action.—Locally capsicum is decidedly irritant, causing dermal heat and redness. It does not vesicate, however, unless long and closely applied to the mucosa. The oleoresin is much more active and causes sharp burning pain and may destroy the epidermis.

Capsicum is a pure, energetic and permanent stimulant. In large doses it produces vomiting, purging, pains in the stomach and bowels, gastro-enteritis, giddiness, strangury, and a species of intoxication and enfeeblement of nerve power. Smaller doses give warmth to the stomach and excite a hyperaemic state of the gastric mucosa, with increased secretion and accelerated movement of the musculature of the stomach and bowels. It slightly increases the urine, and is mostly eliminated by the kidneys.

Therapy.—External. Tincture of Capsicum is an important topical stimulant, rubefacient and counter-irritant. By its revulsive action it often relieves local pain. Painted upon chilblains it quickly gives relief. The pure tincture alone, or mixed with glycerin or mucilage of acacia, may be used. Applied to an aching tooth it either relieves or aggravates, according to the sensitiveness of the nerve or the degree of inflammation present. We have used it with great satisfaction for pain coursing along the spermatic cord in the lower quadrant of the abdomen. It must not, however, be allowed to come in contact with the tender skin of the scrotum. The tincture has been painted upon the scalp to excite the growth of hair in alopecia. With or without glycerin or mucilage of acacia it may be used to clear up ecchymoses. Dry capsicum in the shoes was one of Scudder's favorite means of warming cold feet. Diluted tincture of capsicum, or capsicum with vinegar, and sometimes with salt, is a common and useful stimulating gargle for sluggish forms of sore throat, and sometimes apparently aborts tonsillitis. Capsicum may be used for many of the revulsant effects required of mustard. It does not blister nor cause strangury when so applied. Either the tincture painted upon the part or the capsicum plaster may give relief to so-called chronic rheumatic pains, and be applied in lumbago, pleurodynia and intercostal neuralgia. A stupe of hot water and capsicum applied to the nape of the neck sometimes relieves the headache of debility.

Internal. Capsicum is a pure stimulant to the heart and circulation, giving increased force and slightly augmented frequency to the pulse. One thoroughly acquainted with the action of capsicum can scarcely comprehend why physicians seek for habit-forming stimulants which do infinite harm when so simple and efficacious and pure a stimulant as capsicum may be had. Used within proper dosage it can scarcely do harm, and generally results in incalculable good. Not merely for temporary purposes is capsicum efficient, but its effects are more or less permanent. Naturally it should be selected for atonic conditions and avoided where irritation or active inflammation is present. Nevertheless, in low grades of inflammation and fever, with sluggish blood current, it is a most efficient and necessary stimulant when given in small doses.

The infusion of capsicum is a simple domestic remedy for acute colds, sore throat and hoarseness. Small doses of the tincture are of the utmost value in debility with deficient gastric action. When the membranes are pale, relaxed or flabby, and secretion is impaired or scanty and viscous, capsicum will do more than any other agent to rectify the condition and prepare the way for the action of other medicines. Even where the tongue is dry and elongated and parched from lack of secretion, and the glands of the mouth are inactive, no agent is superior nor safer than capsicum. It has, therefore, wide usefulness in disease-acute, subacute, or chronic. For chronic gastric catarrh it may be used occasionally, but should not be long continued lest it increase the malady sought to be improved. It is invaluable in some cases of atonic dyspepsia, with deficient secretion. It is often promptly effective in gastric flatulence, and is an agent of great value to prevent the accumulation of gases in both stomach and intestines. A mixture of capsicum, vinegar, and salt will sometimes prove a good antiemetic if given in small doses diluted with cold water.

Capsicum should be largely used in low forms of fever-the more depressed the type the more it is needed. It is then of great advantage to maintain the equilibrium of the secretions and the circulation. Capsicum stimulates the appetite, aids digestion, facilitates peristalsis, and is, therefore, both stimulant and tonic to the gastro-intestinal tract. It thus maintains the integrity of those functions-an important desideratum during fevers and in convalescence therefrom. In grave cases of typhoid fever, with almost complete suppression of natural secretions, we would be at a loss without capsicum. It sometimes checks a congestive chill, and in intermittent fever it aids the action of quinine and other antiperiodics.

Capsicum is of very great value in alcoholic delirium. If secretions are suppressed and food can not be taken, or if sleep can not be induced in delirium tremens, one faces an extremely dangerous and perhaps fatal issue. But if secretions can be re-established and food be retained, sleep is very apt to follow. Then the battle against death is won. For this purpose no agent will accomplish so much as capsicum. It may be given at first in frequent small doses in hot water; then as the stomach responds, in larger doses in a good, strong beef broth. While capsicum is best in subacute forms of delirium tremens and not the violent and boisterous type it sometimes is needed after the latter to satisfy the craving for stimulants, to overcome the sinking sensations at the pit of the stomach, to prevent morning nausea and vomiting, to restore tone, and to render the stomach tolerant of food. There is scarcely any danger of giving an overdose of capsicum in dipsomania, as large quantities are swallowed with evident relish and without ill results by confirmed dipsomaniacs. Some cases must have alcohol, but most cases respond to capsicum. Then nux vomica, hydrastis, black haw, hydrochloric acid, and other peptics may follow.

Capsicum is of value in many functional nervous troubles with debility and repressed secretions, and for the aged it is one of the few medicines that should be widely heralded for its power to stimulate and preserve gastric tone and prolong life. In the debility of the young or old, but particularly in old persons, when the body-heat is low, vitality depressed, and reaction sluggish, it is an agent of power for good. Tired, painful muscles, stiffened joints, and relaxation of tissue are common conditions in the elderly that are, in a measure at least, helped by capsicum.

Capsicum in very small doses is said to control irritation and stimulate renal capillary activity in chronic renal congestion. In similar doses it may relieve sluggish hemorrhoids, diarrhea and dysentery, with tenacious muco-bloody stools, with tenesmus and burning, associated with cramplike action of the bladder. These cases are usually encountered in individuals with a lax habit of body. For chronic, non-burning hemorrhoids with torpor and constipation, or relaxation, Locke advised Rx Capsicum, 2 grains; Aloes, 1/4 grain. Mix. Make 1 pill.

Capsicum, internally administered, will frequently check frontal neuralgia, particularly if of malarial origin. It is best to give a few preparatory doses and then follow with quinine associated with it. One of our favorite medicines for masked malarial conditions is an hydrochloric acid solution of quinine with capsicum added.

If called upon to say when capsicum is most valuable, we would limit it to: (a) An agent to re-establish repressed or suppressed secretion; (b) to a medicament for the gastric incompetence of the aged; (c) and to a saving remedy in most cases of acute alcoholism. The dose of capsicum for most purposes need not be large, from the fraction of a drop of a good tincture to ten drops; or the specific medicine not to exceed 2 drops. Only in extreme conditions, as in delirium tremens, are large doses, even in excess of ten drops, required. Fluid preparations of capsicum are to be preferred to powdered capsicum for internal use on account of the rectal discomfort occasioned by the latter. Food for the aged and debilitated may be well fortified with capsicum, and frequently sauces, catsup, and like preparations containing it will be found grateful to such patients.

The Eclectic Materia Medica, Pharmacology and Therapeutics, 1922, was written by Harvey Wickes Felter, M.D.