Olive Oil, Sweet Oil.
A fixed oil obtained from the ripe fruit of Olea europaea, Linné (Nat. Ord. Oleaceae). The olive tree of Asia and southern Europe; cultivated.
Description.—A pale yellow or light greenish-yellow oil, of slight odor and taste, followed by feebly acrid after-taste. Slightly dissolved by alcohol, but miscible with chloroform and ether. Dose, 2 fluidrachms to 2 fluidounces.
Principal Constituents.—Olein (72 per cent), palmitin (28 per cent), and arachin.
Action.—Emollient and demulcent, nutritive and mildly aperient.
Applied to the skin it is protective and softening, and when accompanied, by massage is readily absorbed and appropriated by the system. When swallowed it has little effect in the stomach other than that of a lubricant, but is, partly at least, emulsified and saponified upon reaching the intestines. Here it parts with its olein which becomes a part of the general fat of the body, while excessive quantities pass by way of the intestines and the unassimilated absorbed portion, by way of the renal tract. In contact with the conjunctiva olive oil is irritating.
Therapy.—External. Sterile olive oil is a good lubricant for sounds, bougies, and catheters. To facilitate the passage of a catheter inject through it into the urethra warm olive oil to distend the passage. Masseuers sometimes employ it in their manipulations of the body, but it is less useful than wool fat or cacao butter. It is the safest oil to drop into the auditory canal to kill live insects and facilitate their removal afterward by syringing with warm water. It deprives the insects of oxygen, thus causing their death. Olive oil is sometimes applied to burns and scalds, but is less valuable than lime liniment (Carron Oil). Applied warm it gives relief from the pain of insect stings and bites. It may be used for anointing bruises and excoriations, and is especially useful to prevent excoriations from acrid discharges. It causes too much smarting, however, to use upon the chafed surfaces of infants. Poured over the surface it mitigates the pain and unites to chemically form a soap in cases of external poisoning by caustic alkalies. It is sometimes comforting in sunburn and other acute forms of dermatitis. Dropped warm into the aural canal it frequently relieves earache, but has no advantage over warm water for this purpose. Injected into the rectum it removes ascarides, and sometimes soothes when so used in dysentery and colitis. It is the most commonly employed softening agent for cutaneous crusts, such as those of eczema, seborrhea, favus, and psoriasis. Inunctions of olive oil may be used in malnutrition and wasting diseases, but are far less valuable than cod liver oil for this purpose. It is, however, readily absorbed and thus serves as a food. In the desquamative stage of the eruptive diseases it relieves burning, itching, lowers temperature by quieting the patient, and prevents the dissemination of infective scales. It is particularly useful in scarlet fever. Olive oil is frequently used as the carrier of local anodynes and anaesthetics, as morphine, menthol, camphor, phenol, etc. A warm, olive-oil solution of camphor is a most effective agent in mastitis, both to relieve the tensive pain and to lessen the secretion of milk. It enters largely into the formation of ointments, cerates, liniments, and plasters.
Internal. In doses of one to two ounces olive oil may purge, but it is often uncertain and ineffective as a laxative. When one is inclined to dyspepsia it tends to increase the digestive difficulty. It is commonly given to infants as a laxative in constipation, but while it sometimes relieves it more often disturbs by creating a mild dyspepsia. Pediatricians now generally hold it more harmful than useful in infantile constipation. It may, however, be used by adults exposed to opportunities for lead constipation and in lead poisoning, to prevent absorption of, and overcome the constipating effect of the metal. While of undoubted utility in some cases of cholelithiasis, by indirectly causing a greater increase in the watery constituent of the bile, it is probably of no other value in the gall-stone diathesis. Certainly it does not dissolve the concretions in the gall duct no matter how readily it may affect the solution of cholesterin outside the body. In the intestines it is converted into a soap, and saponaceous particles have been mistaken for expelled gall-stones. Notwithstanding, it is extensively used and advised by physicians to the extent that the laity now consider it the great essential in the treatment of gall-stone disease. The effect of its long-continued use is to derange both the stomach and the bowels. We have seen a persistent diarrhea follow the prolonged use of the oil.
Olive oil may be given immediately in poisoning by alkalies and other irritant substances. With the first it combines by saponification, and in the latter acts as a demulcent. It should not, however, be given in either phosphorus or cantharides poisoning, as the activity of these substances through oil solution is decidedly increased.
The Eclectic Materia Medica, Pharmacology and Therapeutics, 1922, was written by Harvey Wickes Felter, M.D.