Aloe (Aloe vera) : Dosing, Safety, Interactions

by MedlinePlus

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Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Standardization

Standardization involves measuring the amount of certain chemicals in products to try to make different preparations similar to each other. It is not always known if the chemicals being measured are the "active" ingredients.

Standardized aloe products are not widely available. Although this is likely not a concern for the use of aloe gel to the skin, it may pose dangers with oral aloe (due to potential lowering of blood sugar levels). Oral aloe preparations often contain 10-30mg hydroxyanthracene derivatives per daily dose, calculated as anhydrous aloin.

Adults (18 years and older)

Topical (on the skin):

General use: Pure Aloe vera gel is often used liberally on the skin. There are no reports that using aloe on the skin causes absorption of chemicals into the body that may cause significant side effects. Skin products are available that contain aloe alone or aloe combined with other active ingredients.

Psoriasis vulgaris: Hydrophilic cream of 0.5% (by weight) of a 50% ethanol extract of aloe, combined with mineral and castor oils, three times daily for five consecutive days per week, for up to four weeks has been studied.

Genital herpes: Hydrophilic cream of 0.5% (by weight) of a 50% ethanol extract, combined with liquid paraffin and castor oil, three times daily on lesions for five consecutive days per week, for up to two weeks has been studied.

Oral (by mouth):

Constipation: The dose often recommended is the minimum amount to maintain a soft stool, typically 0.04-0.17g of dried juice (corresponds to 10-30mg hydroxyanthraquinones). As an alternative, in combination with celandin (300mg) and psyllium (50mg), 150mg of the dried juice/day of aloe has been found effective as a laxative in research.

Diabetes (type 2): 5-15mL of aloe juice twice daily has been used but safety and efficacy of this dose has not been proven.

HIV infection: 1000mg-1600mg of acemannan orally in four equal doses. Effectiveness and safety have not been proven by studies.

Intravenous/Intramuscular:

Four cases of death have been associated with Aloe vera injections under unclear circumstances. Oral or injected use is not recommended due to lack of safety data.

Children (younger than 18 years)

Topical (on the skin):

Topical (skin) use of aloe gel in children is common and appears to be well tolerated.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

People with known allergy to garlic, onions, tulips, or other plants of the Liliaceae family may have allergic reactions to aloe. Individuals using aloe gel for prolonged times have developed allergic reactions including hives and eczema-like rash.

Side Effects and Warnings

The use of aloe on surgical wounds has been reported to slow healing and, in one case, to cause redness and burning after aloe juice was applied to the face after a skin-peeling procedure (dermabrasion). Application of aloe prior to sun exposure may lead to rash in sun-exposed areas.

The use of aloe or aloe latex by mouth for laxative effects can cause cramping or diarrhea. Use for over seven days may cause dependency or worsening of constipation after the aloe is stopped. Ingestion of aloe for over one year has been reported to increase the risk of colorectal cancer. Individuals with severe abdominal pain, appendicitis, ileus (temporary paralysis of the bowel), or a prolonged period without bowel movements should not take aloe. There is a report of hepatitis (liver inflammation) with the use of oral aloe.

Electrolyte imbalances in the blood, including low potassium levels, may be caused by the laxative effect of aloe. This effect may be greater in people with diabetes or kidney disease. Low potassium levels can lead to abnormal heart rhythms or muscle weakness. People with heart disease, kidney disease, or electrolyte abnormalities should not take aloe by mouth. Healthcare professionals should monitor for changes in potassium and other electrolytes in individuals who take aloe by mouth for more than a few days.

Based on a small number of human studies, aloe taken by mouth may lower blood sugar levels. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels may need to be monitored by a healthcare professional, and medication adjustments may be necessary.

Avoid Aloe vera injections, which have been associated with cases of death under unclear circumstances.

Pregnancy and Breastfeeding

Although topical (skin) use of aloe is unlikely to be harmful during pregnancy or breastfeeding, oral (by mouth) use is not recommended due to theoretical stimulation of uterine contractions. It is not known whether active ingredients of aloe may be present in breast milk. The dried juice of aloe leaves should not be consumed by breastfeeding mothers.

Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

Interactions with Drugs

Based on a small number of human studies, aloe taken by mouth may lower blood sugar levels. Caution is advised when taken with medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional. Medication adjustments may be necessary. In addition, insulin may add to the decrease in blood potassium levels that can occur with aloe.

Due to lowering of potassium levels that may occur when aloe is taken by mouth, the effectiveness of heart medications such as digoxin and digitoxin, and of other medications used for heart rhythm disturbances, may be reduced. The risk of adverse effects may be increased with these medications due to low potassium levels.

Caution should be used in patients taking loop diuretics, such as Lasix® (furosemide), that increase the elimination of both fluid and potassium in the urine. Combined use may increase the risk of potassium depletion and of dehydration.

Use of aloe with laxative drugs may increase the risk of dehydration, potassium depletion, electrolyte imbalance, and changes in blood pH.

Application of aloe to skin may increase the absorption of steroid creams such as hydrocortisone. In addition, oral use of aloe and steroids such as prednisone may increase the risk of potassium depletion.

There is one report of excess bleeding in a patient undergoing surgery receiving the anesthetic drug sevoflurane, who was also taking aloe by mouth. It is not clear that aloe or this specific interaction was the cause of bleeding.

Preliminary reports suggest that levels of AZT, a drug prescribed in HIV infection, may be increased by intake of aloe.

Interactions with Herbs and Dietary Supplements

Based on the laxative properties of oral aloe, prolonged use may result in potassium depletion. This may be worsened by the use of licorice root.

Theoretically, use of oral aloe and other laxative herbs may increase the risk of dehydration, potassium depletion, electrolyte imbalance, and changes in blood pH. Possible laxative herbs include alder buckthorn, black root, blue flag rhizome, butternut bark, dong quai, European buckthorn, eyebright, cascara bark, castor oil, chasteberry, colocynth fruit pulp, dandelion, gamboges bark, horsetail, jalap root, manna bark, plantain leaf, podophyllum root, psyllium, rhubarb, senna, wild cucumber fruit, and yellow dock root.

Based on preliminary human data, oral aloe can reduce blood sugar. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment. Possible examples include: American ginseng, bilberry, bitter melon, burdock, fenugreek, fish oil, gymnema, horse chestnut seed extract (HCSE), marshmallow, milk thistle, Panax ginseng, rosemary, Siberian ginseng, stinging nettle and white horehound.

Interactions with Foods

Aloe taken by mouth may interfere with absorption of foods and orally administered drugs. Prolonged oral use of aloe may lead to poor absorbtion of nutrients in the intestine.

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