Active Ingredients. - Castor oil contains a peculiar glyceride, called ricinic acid, C18H34O2, which was formerly supposed to be the purgative principle; but more accurate researches have discountenanced this idea. Buchheim showed the probability, that (as with croton oil) a saponification process, by mixture with the alkaline intestinal fluids, produces the substance which really acts as a purgative. Its action can be imitated by recinate of soda.

Physiological Action. - Truly poisonous symptoms are hardly to be produced by the administration of any practicable dose of the oil; but the seeds, eaten by mistake, have produced violent drastic effects, and even death. Remote effects are scarcely to be proved, except such as are the mere result of depression from violent local action.

Therapeutic Action. - Castor oil is particularly valuable in constipation arising from indurated faeces, or from such as arises from swallowing: acrid substances, or from the accumulation of acrid secretions.

It is likewise employed with great advantage in diseases attended by irritation or inflammation of the bowels, diarrhoea, dysentery, and enteritis.

As a laxative, it operates so speedily and mildly, that it is constantly resorted to where similar operation by medicines of a more powerful nature would cause injury. Hence its value in haemorrhoids; in inflammatory or spasmodic diseases of the urio-genital organs; in inflammation of the kidneys or bladder; in calculous affections, gonorrhoea, and stricture. The advantage of the use of castor oil as a purgative in these disorders cannot be over-estimated.

The same remark applies to affections of the rectum, especially in stricture.

Pregnant women employ it with considerable advantage.

Castor oil is a highly valuable evacuant also for children, for whom it is used, not only in Europe, but in India; and for infants it is the safest of cathartics. A larger relative dose may be given to infants than to adults, probably from their digesting a larger quantity of what is swallowed. (The leaves of the ricinus communis are decidedly galactagogue, and may be given in decoction or fluid extract when such action is desired.)

Preparation and Dose. - Oleum Ricini,

Euphorbiacae Castor Oil Ricinus Communis 13

- j. (15. - 30.)