Uses of this Herb
Asthma
Burns
Common Cold
Constipation
Diabetes Mellitus
Hemorrhoids
Peptic Ulcer
Wounds
  Herbs with Similar Uses
View List by Use
  Drugs that Interact
Summary
Glyburide
Hydrocortisone
Hydrocortisone-containing Medications
  Herbs with Similar Side Effects
View List by Side Effect
  Herbs with Similar Warnings
View List by Warning
  Learn More About
Western Herbalism
Look Up > Herbs > Aloe
Aloe
  Aloe (English)
Aloe vera/Aloe barbadensis/Aloe ferox (Botanical)
Liliaceae (Plant Family)
Aloe barbadensis/capensis (Pharmacopeial)
Overview
Macro Description
Part Used/Pharmaceutical Designations
Constituents/Composition
Commercial Preparations
Medicinal Uses/Indications
Pharmacology
Dosage Ranges and Duration of Administration
Side Effects/Toxicology
Warnings/Contraindications/Precautions
Interactions
Regulatory and Compendial Status
References


Overview

Aloe vera has a long history of use as a medicinal plant, with written record going back to 1750 BC. The plant has a wide variety of uses because different parts of the plant have different medicinal properties. The mucilaginous gel that is most widely associated with aloe vera comes from the inner part of the leaf. It is separated from the pericyclic tubules, specialized cells that are under the epidermis of the leaf. Those cells have a bitter yellow latex or juice that is dried to form a pharmaceutical product called aloe latex. Aloe gel is used for wound healing, both internally and externally. It greatly speeds the healing of many skin injuries, including ulcerations, burns, frostbite, and abrasions. Aloe latex is a powerful cathartic and is used for constipation. Because it can cause painful cramping, it is not used as often as gentler herbal laxatives. Lower doses of aloe latex can be effective in preventing kidney stone formation or reducing their size. Lower doses can also be effective as a stool softener, which is particularly helpful in the case of hemorrhoids.

Aloe gel is now found in many commercial skin-care products, shampoos, and conditioners. But some studies have shown that it does not retain its healing ability when stored. There is now a stabilized form of the gel that may be able to be stored and still retain the healing action, but fresh aloe gel from the leaves is still the best option.

Aloe gel may also be taken internally, often in a liquid form called aloe juice. In this form, aloe can help heal peptic ulcers by inhibiting stomach acids that irritate ulcers. Aloe juice also improves digestion by destroying many bacteria that cause infection.


Macro Description

A perennial plant; yellow flowers; tough, fleshy leaves grow up to 20 inches long, 5 inches across, up to 30 per plant; grows to 4 feet. Grown in most tropical and subtropical locations, including Caribbean, southern United States, Latin America, and the Middle East.


Part Used/Pharmaceutical Designations
  • Leaves

Constituents/Composition

Anthraquinones, aloins, anthranoids, aglycones, polysaccharides (including glycoproteins and mucopolysaccharides), and prostaglandins


Commercial Preparations

Aloe gel is best fresh from an aloe plant. Slit a leaf lengthwise and remove gel. Aloe gel is also available commercially in stabilized form. Aloe latex is available as a powder or in 500 mg capsules for use as a laxative. Aloe juice is available in liquid form.


Medicinal Uses/Indications
  • Aloe was historically used to treat burns.
  • Traditional herbal actions: antibacterial, antifungal, anesthetic, antipyretic, antipruritic, moisturizer, vasodilator, anti-inflammatory, anthelmintic, cathartic, stomachic, demulcent, emmenagogue, laxative combined with carminative, vulnerary
  • Clinical applications: burns (due to radiation, sunburn, and other causes), headaches, dry skin, rashes (due to dermatitis, poison ivy, or insect bites), kidney stones, hemorrhoids, hives, constipation, wound healing, peptic ulcers, immune system enhancement, diabetes, asthma

Pharmacology

Aloe vera contains vitamins C and E and zinc, which are all important for wound healing. Glycoproteins in aloe gel inhibit and break down bradykinin, a mediator of pain and inflammation. Aloe gel also inhibits thromboxane, which also causes inflammation. Aloe gel stimulates fibroblast and connective tissue formation, a healing action that most other anti-inflammatories don't have. The polysaccharides in aloe seem to stimulate skin growth and repair as well. Aloe also increases blood flow to burned tissue, which helps it heal.

Aloe gel has been particularly effective in healing diabetic leg ulcers because along with its other wound healing capabilities, it also lowers blood sugar.

Aloe gel's antibacterial and antifungal ability compares favorably with that of silver sulfadiazine, an antiseptic used regularly in treatment of extensive burns. Aloe vera extract has been shown to kill Pseudomonas aeruginosa, Klebsiella pneumoniae, Serratia marcescens, Citrobacter species, Enterobacter cloacae, Streptococcus pyogenes, Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, Streptococcus faecalis, and Candida albicans.

Aloe's active cathartic component is aloin. In small doses, it gives tone to intestinal muscle. In larger doses, it becomes a strong purgative, increasing colonic secretions and peristaltic contractions in the large intestine. It is harsher on the system than other anthraquinone laxatives, such as cascara and senna. The anthraquinones in aloe latex prevent kidney stone formation by binding calcium in the urinary tract and reducing the growth rate of urinary calcium crystals.

Aloe juice heals peptic ulcers by inhibiting pepsin when the stomach is empty, releasing it only to digest food. It inhibits the release of hydrochloric acid by preventing the binding of histamine to parietal cells. It also heals and prevents other irritants from reaching the ulcer. Aloe juice aids the digestive process by increasing gastric pH, reducing yeast infections, and improving water retention.

Acemannan, an antiviral compound of aloe juice, is a powerful immune system stimulant. It enhances macrophage activity, the function of T cells, and interferon production.


Dosage Ranges and Duration of Administration
  • The dosage for dry aloe extract is very small (50 to 200 mg).
  • For general use: dosage of gel or juice 2 tbsp tid (the standardized aloe product measured to hydroxyanthracene derivatives is not widely available in the USA)
  • For prevention of kidney stones: 2 to 3 tbsp daily
  • For laxative purposes: 500 to 1,000 mg daily (care should be taken that laxative doses of aloe are accompanied by carminative herbs to prevent griping)
  • For burns or wound healing, topically: aloe vera gel applied liberally (fresh gel from aloe plant is best)
  • For hemorrhoids, as a stool softener: dry aloe extract, 0.05 to 0.2 g
  • For constipation: 20 to 30 mg hydroxyanthracene derivatives per day, calculated as anydrous aloin

Side Effects/Toxicology

Aloe gel is safe for external use, unless it causes a rare allergic reaction. Discontinue use if it irritates the skin. It is not useful for treatment of deep, vertical wounds (e.g. cesarean incision). Aloe latex may cause severe intestinal cramps or diarrhea.


Warnings/Contraindications/Precautions

Pregnant or nursing mothers should not ingest aloe latex. It may cause uterine contractions and trigger miscarriage. Contraindicated for gastrointestinal illness, intestinal obstruction, appendicitis, and abdominal pain of unknown origin. May aggravate ulcers, hemorrhoids, diverticulosis, diverticulitis, colitis, and irritable bowel syndrome. If taken over a long time, can cause dependence or disturbance of electrolyte balance. May cause urine to turn a harmless red color. Should not be used for children under 12.


Interactions
Glyburide

In a single blind clinical trial of patients with diabetes mellitus, aloe vera juice (1 tbsp 80% juice bid) combined with glyburide (10 mg glibenclamide) significantly improved blood sugar levels and decreased triglyceride levels (Bunyapraphatsara et al. 1996). Glyburide alone was ineffective. The effects of the combined treatment were not greater than results obtained from treatment with aloe vera juice alone. Blood glucose levels should be monitored carefully in diabetic patients using aloe vera either alone or in combination with other antidiabetic medications in order to avoid potential hypoglycemic complications.

Hydrocortisone

The topical and systemic applications of aloe vera combined with hydrocortisone 21-acetate significantly reduced edema in mice and rats with acute inflammation (Davis et al. 1991). Topically, aloe vera (5%) and hydrocortisone (0.5% aqueous solution) decreased ear inflammation in mice by 85.6%. Systemically, aloe (25 mg/kg and 100 mg/kg) combined with hydrocortisone (0.1 mg/kg and 100 mg/kg) decreased inflammation in rats by 65.7% compared to results obtained from either treatment alone; these solutions were injected on a 10 mg/kg basis to measure the inhibitory effects on paw edema.


Regulatory and Compendial Status

German Commission E approves aloe latex for chronic constipation, with certain reservations.


References

Blitz JJ, et al. Aloe vera gel in peptic ulcer therapy: preliminary report. J Am Osteopath Assoc. 1963;62:731-735.

Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, Mass: Integrative Medicine Communications. 1998.

Bunyapraphatsara N, Yongchaiyudha S, Rungpitarangsi V, et al. Antidiabetic activity of Aloe vera L. juice. II. Clinical trial in diabetes mellitus patients in combination with glibenclamide. Phytomed. 1996;3:245-248.

Castleman M. The Healing Herbs. New York, NY: Bantam Books. 1991.

Danhof I. Potential benefits from orally-injested internal aloe vera gel. International Aloe Science Council Tenth Annual Aloe Scientific Seminar; 1991; Irving, Texas.

Davis RH, Parker WL, Murdoch DP.Aloe vera as a biologically active vehicle for hydrocortisone acetate. J Am Podiatr Med Assoc. 1991;81:1-9.

Duke J. The Green Pharmacy. Emmaus, Pa: Rodale Press; 1997.

Fahim MS, Wang M. Zinc acetate and lyophilized Aloe barbadensis as vaginal contraceptive. Contraception. 1996;53:231-236.

Fulton JE Jr. The stimulation of postdermabrasion wound healing with stabilized aloe vera gel-polyethylene oxide dressing. J Dermatol Surg Oncol. 1990;16:460.

Grindlay D, Reynolds T. The aloe vera phenomenon: a review of the properties and modern uses of the leaf parenchyma gel. J Ethnopharmacol. 1986;16:117-151.

Gruenwald J, Brendler T, Jaenicke C, et al., eds. PDR for Herbal Medicines. Montvale, NJ: Medical Economics Co; 1998.

Heggers J, et al. Beneficial effects of aloe in wound healing. Phytother Res. 1993;7:S48-S52.

Murray M, Pizzorno J. Encyclopedia of Natural Medicine. Rocklin, Calif: Prima Publishing; 1991.

Murray M. The Healing Power of Herbs: The Enlightened Person's Guide to the Wonders of Medicinal Plants. Rocklin, Calif: Prima Publishing; 1995.

Newall C, Anderson L, Phillipson J. Herbal Medicines: A Guide for Health-care Professionals. London: Pharmaceutical Press; 1996.

Plemmons JM, et al. Evaluation of acemannan in the treatment of aphthous stomatitis. Wounds. 1994;6.

Saoo K, et al. Antiviral activity of aloe extracts against cytomegalovirus. Phytother Res. 1996;10:348-350.

Schmidt JM, Greenspoon JS. Aloe vera dermal wound gel is associated with a delay in wound healing. Obstet Gynecol. 1991;78(1).

Shida T, et al. Effect of aloe extract on peripheral phagocytosis in adult bronchial asthma. Planta Med 51. 1985.

Syed TA, et al. Management of psoriasis with aloe vera extract in a hydrophilic cream: a placebo-controlled, double-blind study. Trop Med Int Health. 1996;1:505-509.

Tyler V. The Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies. Binghamton, NY: Pharmaceutical Products Press; 1993.

Vazquez B, et al. Anti-inflammatory activity of extracts from aloe vera gel. JEthnopharmacol. 1996;55:69-75.


Copyright © 2000 Integrative Medicine Communications

This publication contains information relating to general principles of medical care that should not in any event be construed as specific instructions for individual patients. The publisher does not accept any responsibility for the accuracy of the information or the consequences arising from the application, use, or misuse of any of the information contained herein, including any injury and/or damage to any person or property as a matter of product liability, negligence, or otherwise. No warranty, expressed or implied, is made in regard to the contents of this material. No claims or endorsements are made for any drugs or compounds currently marketed or in investigative use. The reader is advised to check product information (including package inserts) for changes and new information regarding dosage, precautions, warnings, interactions, and contraindications before administering any drug, herb, or supplement discussed herein.