Senna is a certain, manageable, and convenient cathartic, very useful in all forms of febrile diseases in which a laxative action is desired, particularly in the forming stage of bilious and other fevers, especially in children, and in other diseases where a severe impression on the bowels is not desired. Constipation does not follow its employment. It is also efficient in flatulent and bilious colics. Its influence is chiefly exerted on the small intestines, augmenting their mucous secretions, exciting increased peristaltic motion, and producing loose, yellowish-brown evacuations. A nursing infant may be purged by the milk of the mother who has taken senna, and so susceptible are some persons to its action, that its odor is said to induce a cathartic action. It does not act as a sedative, as is the case with some other cathartics, nor as a refrigerant; but has a slight stimulating influence, insufficient, however, to contraindicate its use in case of general excitement or reaction. Besides the nauseating taste of senna, it is apt to cause sickness at stomach, and very few persons can use it alone, without experiencing more or less griping pains and flatulence. The addition of cloves, ginger, cinnamon, or other aromatics, are excellent correctives of these unpleasant effects. A teaspoonful of cream of tartar to a teacupful of the decoction or infusion of senna, is a mild and pleasant cathartic, particularly suited for females, where it may be required soon after delivery. The addition of neutral laxative salts, as phosphate of sodium, Epsom, or Rochelle salts, is another mode, adopted by a certain class of practitioners, of preventing the tormina, and, at the same time, increasing the activity of the infusion of senna. These are, however, rarely used by Eclectics. Saccharine and aromatic substances are also combined for this purpose, as sugar, manna, aromatic seeds, electuary of senna, etc. The purgative effect of senna is much increased by the addition of the pure bitters; the decoction of guaiacum is said to answer a similar purpose. Senna is contraindicated in an inflammatory condition of the alimentary canal, or even irritation of those parts, general debility, hemorrhoids, prolapsus ani, etc. The dose, in powder, is from 30 to 50 grains; in tincture, from ½ to 2 fluid ounces; specific senna, 1 to 60 drops; electuary, 2 drachms; and of the infusion, which is the most usual mode of administration, from 2 to 4 fluid ounces. But, according to Mr. T. B. Groves, the tincture of senna is without action; the decoction is of less value than the infusion, and the infusion less than maceration; the solution by maceration alone purges without gripings, as by this method the larger portion of the cathartic principle is extracted, leaving behind the acrid constituents. Cathartic acid has the same action of senna, purging with griping in doses of 1½ to 3 grains. The seed-pods and leaf-stalks of senna are slower to act than senna, but are freer from griping and nauseating effects than the leaves.
Specific Indications and Uses.—Wind or bilious colics; a laxative for non-inflammatory conditions of the intestinal tract.