The dried juice of the leaves of several species of Aloe: (1) Aloe Perryi, Baker; (2) Aloe vera, Linné;(3) Aloe ferox, Miller. (Nat. Ord. Liliaceae). Barbadoes, Africa and the Orient.
Common Names: (1) Socotrine Aloes; (2) Curaçoa Aloes; (3) Cape Aloes.

Description.—(l) Yellow-brown or black-brown masses, aromatic, bitter, and nauseous, half of which is soluble in water; powder, deep brown; aqueous solution yellowish. (2) Orange to black-brown masses, waxy, not aromatic; more than half soluble in water; powder, deep red-brown; aqueous solution, purplish red. (3) Red-brown or greenish-black, smooth, glassy masses, more than half soluble in water; powder, greenish-yellow (fresh), light brown (old); aqueous solution, pale yellow. Dose, 1 to 8 grains.

Principal Constituents.—Aloin (C14H10). resin, and volatile oil.
Preparations.—(1) Aloinum, Aloin (a very bitter, yellow-to-dark-yellow, finely-crystalline powder, soluble in water, slightly in ether). Dose, 1/12 to ½ grain.
2. Pilulae Aloes, Pills of Aloes. (Each pill contains 2 grains of Aloes.) Dose, 1 to 2 pills.
3. Tinctura Aloes, Tincture of Aloes (10 per cent of Aloes). Dose, 15 to 60 minims.
Specific Indications.—Atony of the large intestine and rectum; mucoid discharges, prolapsus ani, ascaris vermicularis (Scudder). Difficult evacuation of the lower bowel when not due to fissure or inflammation.

Action.—Aloes is a slow-acting stimulating purgative, probably affecting only the lower bowel, notably the rectum. In small doses it is laxative. It strongly increases colonic peristalsis, but does not greatly increase the secretions of the intestinal glands, consequently the stools are feculent rather than watery, unless the dose be large. As it takes from 10 to 15 hours to operate, it should be administered in the early evening so that evacuation may occur in the morning. When given alone it causes considerable griping and often rectal fullness and heat. These may be modified by giving it in pill with soap or an alkaline carbonate, or with hyoscyamus, belladonna, or carminatives. Sulphate of iron slightly restrains its action and ipecac increases it. Applied to a denuded surface it operates the same as if taken internally, and administered to a nursing mother it purges the sucking child. By its stimulating action upon unstriped fibre, as of the bowel and uterus, and its tendency to excite the pelvic circulation producing pelvic congestion, it proves emmenagogue. It is a purgative for torpor and debility, and should not be given to plethoric persons, nor when gastro-enteritis, or actively inflamed hemorrhoids are present; nor when pregnancy exists.

Therapy.—Aloes, in ½ to 1 grain doses, is a gastric stimulant of value in atonic indigestion, with obstinate constipation. It has had a large vogue as an after-dinner pill, but is now little used for that purpose. As a rule it is a good agent for use in atonic chronic constipation, but should never be exhibited in cathartic doses for this purpose. Aloes, or its derivative, aloin, is usually an ingredient of many favorite laxative pills, composed of varying amounts of either drug in combination with belladonna, strychnine, and ipecac, and sometimes with the addition of capsicum. One of the best of these is the "Lapactic pill." When sulphate of iron is indicated in chlorosis and anemia, aloes is generally combined with it. It has the effect of restraining the constipating action of the chalybeate. Aloes and iron are both very useful in delicate women who are subject to amenorrhoea or menorrhagia, with pelvic and intestinal torpor, poor appetite, and a weak circulation. As most of these cases are profoundly constipated, the explanation of the combination may be found in the laxative action of the aloes. When hemorrhoids are due to feeble venous return, small doses of aloes or aloin may improve conditions, but it should never be given when there is active hemorrhoidal inflammation. In very small doses aloin is useful in rectal prolapsus, due to pelvic debility and general ill-health. It is still a debatable question whether aloes influences the flow of bile. When, however, jaundice is coexistent with torpor of the hemorrhoidal veins, it may be improved by laxative doses of aloes or aloin. Aloes is a decidedly useful but much abused medicine in chronic or habitual constipation. As stated above only slightly laxative amounts should be used. When a purgative is needed for bowel impaction in the insane—particularly in hypochondriasis and melancholia—aloes is probably the best that can be given. The improvement in the mental state often will be commensurate with the betterment of the intestinal torpor.

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