Aloe (Aloe barbadensis, Aloe capensis)

Published August 21, 1985; Replaced July 21, 1993.
List of German Commission E Monographs (Phytotherapy)


Name of Drug

Aloe barbadensis, Curaçao aloe.
Aloe capensis, Cape aloe.

Composition of Drug

Curaçao aloe consists of the dried latex of the leaves of Aloe barbadensis Miller [syn. A. vera (L.) N. L. Burm.] [Fam. Liliaceae], as well as its preparations in effective dosage.

Cape aloe consists of the dried latex of the leaves of several species of the genus Aloe, especially A. ferox Miller and its hybrids, as well as their preparations in effective dosage.

Aloe contains anthranoids, mainly of the aloe-emodin type. These drugs must conform to the currently valid pharmacopeia.

Pharmacological Properties, Pharmacokinetics, Toxicology

1,8-dihydroxy-anthracene derivatives have a laxative effect. This effect is primarily caused by the influence on the motility of the colon, an inhibition of stationary and stimulation of propulsive contractions. This results in an accelerated intestinal passage and, because of the shortened contraction time, a reduction in liquid absorption. In addition, stimulation of the active chloride secretion increases the water and electrolyte content.

Systematic studies pertaining to the kinetics of aloe preparations are not available; however, it must be supposed that the aglycones contained in the drug are already absorbed in the upper small intestine. The ß-glycosides are prodrugs which are neither absorbed nor cleaved in the upper gastrointestinal tract. They are degraded in the colon by bacterial enzymes to aloe-emodin anthrones. Aloe-emodin anthrone is the laxative metabolite. In humans, rhein was demonstrated in the urine after consumption of 86 and 200 mg of aloe powder.

Active metabolites, such as rhein, infiltrate in small amounts into the milk ducts. A laxative effect on nursing infants has not been observed. The placental permeability for rhein is very small.

Drug preparations [i.e., herbal stimulant laxative drugs] have a higher general toxicity than the pure glycosides, presumably due to the content of aglycones. An aloe extract containing 23 percent aloin and less than 0.07 percent aloe-emodin, as well as aloin, produced no mutagenic effects in bacterial and mammalian test systems. For aloe-emodin, emodin and chrysophanol, partially positive results have been obtained. There are no available data regarding carcinogenicity.

Clinical Data 1. Uses Constipation.

2. Contraindications

Intestinal obstruction, acutely inflamed intestinal diseases, e.g., Crohn's disease, ulcerative colitis, appendicitis, abdominal pain of unknown origin. Not to be prescribed to children under 12 years of age or during pregnancy.

3. Side Effects

In single incidents, cramp-like discomforts of the gastrointestinal tract. These cases require a dosage reduction.

Long-term use/abuse: disturbances of electrolyte balance, especially potassium deficiency, albuminuria and hematuria. Pigment implantation into the intestinal mucosa (pseudomelanosis coli), is harmless and usually reverses upon discontinuation of the drug. The potassium deficiency can lead to disorders of heart function and muscular weakness, especially with concurrent use of cardiac glycosides, diuretics and corticosteroids.

4. Special Caution for Use

Stimulant laxatives must not be used over an extended period of time (1 - 2 weeks) without medical advice.

5. Use During Pregnancy

Because of insufficient toxicological investigation, this drug should not be used during pregnancy and lactation.

6. Interactions with Other Drugs

With chronic use/abuse, due to loss in potassium, an increase in effectiveness of cardiac glycosides is possible, as well as an effect on antiarrhythmic agents. Potassium deficiency can be increased by simultaneous application of thiazide diuretics, cortico-adrenal steroids, and licorice root.

7. Dosage

Aloe powder, aqueous and aqueous-alcoholic extracts in powdered or liquid form, for oral use.

Unless otherwise prescribed:

20 - 30 mg hydroxyanthracene derivatives/day, calculated as anhydrous aloin. The individually correct dosage is the smallest dosage necessary to maintain a soft stool.

Note: The form of administration should be smaller than the normal daily dosage.

8. Overdosage

Electrolyte and fluid imbalance.

9. Special Warnings

Usage of a stimulating laxative for longer than the recommended short-term application can cause an increase in intestinal sluggishness.

The preparation should be used only if no effects can be obtained through change of diet or usage of bulk-forming products.

10. Effects on Operators of Vehicles and Machinery

None known.

Note: During the course of treatment, a harmless red color may occur in the urine.