A fixed oil expressed from the seeds of Ricinus communis. Calcutta.

Fig. 221.3   Castor Oil Seeds.

Fig. 221.3 - Castor Oil Seeds.

Characters. - Viscid, colourless, or pale straw-yellow, having a slightly nauseous odour, and a somewhat acrid taste.

Composition. - Yields several fatty acids, including ricinoleic acid, peculiar to castor oil. The seeds contain an alkaloid, ricinine (not purgative), also an acid drastic principle, of which only a small proportion is separated with the oil.

Dose. - One fl. dr. to 1 fl. oz.

Preparations.

B.P.

Dose.

Collodium Flexile..............................................................................

For external use.

Linimentum Sinapis Compositum (p. 516).........................................

,,

Pilula Hvdrargyri Subchloridi Composita (p. 522).....................................

5-10 gr.

U.S.P.

Linimentum Sinapis Compositum (p. 517).........................................

For external use.

Collodium Flexile...............................................................................

,,

Action and Uses. - Castor oil is one of our best purgatives, as it leaves no injurious effects, and can be given whenever purging is wanted without any irritant effect, as in children, pregnant women, piles and fissure of anus, or after parturition, and to delicate people. Its nauseous taste is its only objection. It is one of the best remedies for acute diarrhoea, given in one dose of 1/4 to 1/2 fl. oz. with 5-10 min. of laudanum. This removes any irritating substances (p. 388) and soothes the intestine. In chronic dysentery 15 min. of castor oil and 5-10 min. of tincture of opium given three times a day is a useful remedy. In lead colic it acts as a preventive to constipation, and has been used as a curative agent (p. 700). It is better, however, to give potassium iodide and sulphate of magnesium. A drop of castor oil dropped into the eye will often allay the irritation produced by a particle of sand, etc. As a local application, castor oil or poultices of the leaves of the castor-oil plant, are used to the breasts in order to promote the secretion of milk. The oil is useful rubbed into the skin in seborrhoea.

Administration. - If the oil be given the first thing in the morning an hour before breakfast, ten or twenty drops are generally sufficient to open the bowels. This dose may be given in a teaspoonful of peppermint-water or brandy. The brandy should be added in such proportion that the oil neither sinks nor swims in the mixture. The same mixture of peppermint-water and brandy answers well as a vehicle for the administration of larger doses also. In all cases the glass, cup, or spoon should be thoroughly wetted first with water or peppermint-water to prevent the oil adhering to the side. A little brandy is then to be mixed with the peppermint-water, the oil carefully poured over the middle of it, and then more brandy added. If the whole be drunk at one draught the taste of the oil is not perceived. Lemon-juice, coffee, and the froth of porter are also used as vehicles for the administration of castor oil. It may also be given in capsules, which are perfectly tasteless.