Concentrated, Dried Sap
The concentrated, dried latex of the leaf, used as a stimulant laxative — carries the strongest precautions.
Sap (Latex)
French Pharmacopoeia List A (Sap & Gel)
Biological Overview
Aloe vera is a succulent plant with thick, fleshy leaves, spiny at the edges, gathered in a dense rosette atop a trunk of variable length. The leaves store water reserves in the interior parenchyma to withstand drought, and the plant produces yellow flowers (Barbados aloe) — a related species, Cape aloe, produces red flowers. More than 150 species of Aloe exist, and about ten of these supply the "officinal" aloe used medicinally.
FamilyAsphodelaceae
Gel Water Content98.5–99.5%
Sap Hydroxyanthracenes25–40%
Gel ContraindicationsNone Known
Botanical Classification
Taxonomy & Identification
- Latin Name
- Aloe vera (L.) Burm.
- Synonym
- Aloe barbadensis Miller
- Family
- Asphodelaceae (formerly Liliaceae)
- Common Names
- Barbados Aloe, Aloe Vera
- Parts Used
- Leaf sap (latex), leaf gel
- Related Species
- Aloe ferox (Cape aloe), Aloe succotrina
⚠ Two Products From One Leaf
This monograph covers Barbados aloe (Aloe vera/Aloe barbadensis) and, where documented jointly, Cape aloe (Aloe ferox). Both are also related to Aloe succotrina (syn. Aloe socotrina). Critically, the leaf yields two very different products — the sap and the gel — with entirely separate safety profiles covered throughout this page.
Ethnobotany & Traditional Use
History & Tradition
Aloe was known to ancient Greece and was used by the Egyptians to embalm mummies — it is said to have been used to embalm the body of Christ. Christopher Columbus considered it a panacea.
Cape aloe historically entered into the composition of the "Swedish Elixir," a traditional bitter tonic. Modern research has since drawn a sharp distinction between the sap's stimulant-laxative pharmacology and the gel's wound-healing, anti-inflammatory and immunomodulant properties.
Two Products, One Leaf
Gel vs. Sap — Deep Dive
The single most important distinction in this monograph: the sap and the gel come from different tissues within the same leaf and behave as two almost entirely separate substances.
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The Sap (Latex)
Flows naturally from cut leaves stood vertically, and is concentrated by boiling. Rich in hydroxyanthracene derivatives (25–40%), it is a powerful colon stimulant laxative — and carries the majority of this plant's safety risk.
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The Gel
Formed by the mucilage of the leaf's central cells, 98.5–99.5% water. Used in cosmetics and slimming products, it is wound-healing and anti-inflammatory, with no known contraindications.
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Sap Mechanism: Anthrone Release
Anthracene derivatives reach the active site in the colon, where intestinal flora enzymes release the corresponding anthrones, which stimulate intestinal peristalsis and secretions.
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Gel Mechanism: Hydration & Polysaccharides
The gel's wound-healing effect is attributed to its polysaccharide content and exceptionally high water content, supporting tissue repair and reducing inflammation. [7]
Pharmaceutical Preparations
Parts Used & Available Forms
The concentrated, dried leaf sap and the leaf gel are the two parts used, with distinct galenic forms.
Inner-Leaf Gel
Mucilage from the leaf's central cells — the safe form, used topically and orally.
Gel
Mother Tincture (Sap)
Mother tincture of Aloe ferox sap — this is the sap, not the gel, and carries the sap's precautions.
Tincture (Sap)
Clinical Dosimetry
Dosages
No standardized usual dose is established for either the sap or the gel; the dose used in a featured gel trial is included below for reference.
Phytochemistry
Composition
The sap and the gel have entirely distinct documented compositions.
Sap (Latex)
Hydroxyanthracene DerivativesAloins A & B (barbaloin), esters, aloe-emodol, chrysophanol
25–40%Resinous FractionAloesone, aloeresins; 7-hydroxy-aloins (Barbados); aloinosides (Cape)
PresentGel
WaterDominant component
98.5–99.5%MineralsChiefly potassium (4.0–4.3%), calcium (2.5–3.6%); dry-matter basis
16–25%PolysaccharidesNeutral acetyl-glucomannan mucilages (3.6–15%); dry-matter basis
8.0–15.6%Simple SugarsGlucose (~12%), fructose (~5%); dry-matter basis
PresentProteinsDry-matter basis
3.7–8.9%Organic AcidsChiefly malic acid; dry-matter basis
20.2–22.7%🟤
Powerful Colon Laxative (Sap)
The sap that flows naturally from cut leaves, concentrated by boiling, is a powerful stimulant laxative for the colon.
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Wound-Healing (Gel)
The mucilaginous gel is wound-healing, attributed to its polysaccharide content and high water content. [7]
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Anti-Inflammatory (Gel)
Documented anti-inflammatory activity, including via the arachidonic acid and cyclooxygenase pathway, and against a spectrum of irritants. [8][9][18][19]
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Antidiabetic (Gel)
Documented antidiabetic activity, with anti-inflammatory effects specific to diabetic models. [10][11]
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Immunomodulant (Gel)
Documented immunomodulant activity, including macrophage activation, and a protective effect against tumor development in vitro. [12][13][15]
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Thyroid Function Support (Gel)
100mL/day of Aloe barbadensis juice for 9 months improved thyroid function and reduced inflammation and autoimmunity in women with subclinical Hashimoto's hypothyroidism. [16]
☀️
Sunburn & Radiation Erythema (Gel)
Documented anti-inflammatory activity in the ultraviolet erythema test, with modest results reported specifically for radiation-induced skin toxicity. [21][22]
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Ulcerative Colitis Support (Gel)
A randomized, double-blind, placebo-controlled trial studied oral Aloe vera gel in active ulcerative colitis. [27]
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Cosmetic & Slimming Use (Gel)
Used in cosmetics and slimming products, reflecting the gel's soothing, moisturizing mucilage properties.
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Gingival & Ocular Application (Gel)
Documented benefit for gingivitis, and even conjunctivitis when fresh pulp is applied locally. [25][26]
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Refreshing & Antimicrobial (Gel)
The gel is edible, described as "refreshing," and carries antimicrobial, anticoagulant and anti-inflammatory properties.
Clinical Applications
Clinical Indications
Documented uses, split by part — the sap's single indication carries real precautions; the gel's indications are broad.
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Sap — Single Indication
Short-Term Use Only
- Acute constipation: documented indication, not for prolonged use.
- Antiherpetic: attributed to aloe-emodine.
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Gel — Wounds & Skin
Broadest Documented Indication Set
- Wounds, ulcers, burns, sunburn: documented indication, including radiation-related skin effects (modest results). [21]
- Chapped skin, chilblains, irritations, pruritus: documented indications.
- Infected wounds, skin inflammation, gingivitis: documented indications. [25]
- Conjunctivitis: fresh pulp applied locally. [26]
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Gel — Digestive & Metabolic
Colitis, Thyroid & Cosmetic Use
- Ulcerative colitis & inflammatory bowel disease: documented indication. [27]
- Hashimoto's thyroiditis with subclinical hypothyroidism: a preliminary, not yet firmly established indication.
- Cosmetic use & wound healing: documented indication.
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Gel — Dermatologic (Topical)
Combined Applications
- Psoriasis (topical): in combination with propolis, applied locally. [28]
Pharmacodynamics
Mode of Action
The sap's mechanism is well characterized; the gel's effects are attributed mainly to its physical and polysaccharide properties.
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Sap: Anthrone-Mediated Colon Stimulation
Anthracene derivatives in the sap reach the colon's active site, where intestinal flora enzymes release the corresponding anthrones. These stimulate intestinal peristalsis and secretions, while reabsorption of water and electrolytes is inhibited by blocking enterocyte Na-K-ATPase activity and via action on prostaglandins.
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Gel: Polysaccharide & Hydration-Based Repair
The gel's wound-healing and anti-inflammatory effects are attributed to its high polysaccharide content and exceptionally high water content, supporting tissue hydration and repair rather than acting through a single defined pharmacological target.
Clinical Safety
Safety, Interactions & Precautions
The sap and the gel have almost entirely separate safety profiles — read the distinction carefully before use.
⚠ Sap (Latex) — Serious Risks, Strongly Discouraged
The Primary Source States Sap Use Is "Strongly Discouraged"
- Pregnancy: explicitly forbidden.
- Stated lethal dose: approximately 1 gram per day over several days.
- Electrolyte disturbance: causes diarrhea, hydro-electrolytic disturbances, and potassium loss leading to intestinal muscle paralysis — which in turn reduces laxative effectiveness and drives dose escalation. [29]
- Irreversible mucosal disruption: can cause spasms, mucus loss and risk of laxative dependence syndrome.
- Cardiac caution: use with caution in heart failure.
- High-dose uterine effect: can induce pelvic congestion and reflex uterine stimulation at high doses.
✓ Gel — No Known Contraindications
A Markedly Different Safety Profile
The gel has no known contraindication. This applies specifically to the inner-leaf gel — not the sap — and underscores why product labeling and part identification genuinely matter for this plant.
Notable Non-Pathological Finding
- Brown mucosal discoloration: not pathological on its own, but indicates melanosis coli (rectal melanosis) from chronic sap/anthraquinone laxative use.
Drug Interactions (Applies Broadly)
- CYP3A4 & CYP2D6 inhibition: documented, with real interaction risk alongside certain anticancer drugs (bortezomib, gefitinib, imatinib) and tamoxifen.
- Product authenticity: commercial gels are sometimes subject to harmless-seeming adulteration — dilution, added dextrins or other sugars and minerals, or whole-leaf processing with activated charcoal instead of using only the central parenchyma. Published US monographs and certifications only screen out the crudest forms of adulteration.
Clinical Disclaimer: This monograph is for educational and professional reference only. It does not constitute medical advice, diagnosis, or treatment guidance. Always consult a qualified healthcare provider before initiating any phytotherapeutic regimen, particularly regarding the sap/latex form, which carries genuine and serious risks distinct from the gel.
Common Questions
Frequently Asked Questions
What is Aloe vera traditionally used for?
Aloe was known to ancient Greece, used by Egyptians to embalm mummies, and is said to have been used to embalm the body of Christ. Christopher Columbus considered it a panacea. Traditionally, the concentrated sap has been used as a colon laxative, while the inner gel has been used for wound healing and skin care.
What is the difference between Aloe vera gel and Aloe sap (latex)?
They come from different parts of the leaf and behave very differently. The sap (latex) drains naturally from cut leaves and is concentrated by boiling; it is a powerful colon stimulant laxative with real safety risks. The gel comes from the mucilage of the leaf's central cells; it has no known contraindications and is used for wound healing, skin care and anti-inflammatory purposes.
Is Aloe vera gel safe to use?
Yes. There is no known contraindication for the gel. This is in sharp contrast to the sap, which carries genuine risks and strong precautions.
Is Aloe vera sap (latex) safe to use?
No, not without real caution. Its use is strongly discouraged: it is forbidden during pregnancy, can cause diarrhea and electrolyte disturbances, potassium loss leading to reduced effectiveness of laxatives, irreversible disruption of the intestinal mucosa with cramping and mucus loss, and a stated lethal dose of around 1 gram per day over several days.
Does Aloe vera gel help wounds and burns heal?
Yes, this is one of its best-documented uses. The mucilaginous gel, rich in polysaccharides and water, has demonstrated wound-healing and anti-inflammatory activity, and is used for wounds, ulcers, burns, sunburn, chapped skin, and infected wounds.
Does Aloe vera help with diabetes or thyroid function?
Preliminary evidence points this way. Aloe vera gel has shown antidiabetic activity and anti-inflammatory effects in diabetic models. In a study of women with subclinical Hashimoto's hypothyroidism, daily intake of 100 mL of Aloe barbadensis juice for 9 months improved thyroid function and reduced thyroid inflammation and autoimmunity, though this remains a preliminary, not yet firmly established, indication.
Can Aloe vera interact with medications?
Yes. Aloe vera is documented as an inhibitor of the CYP3A4 and CYP2D6 enzymes, creating real interaction risk with certain anticancer drugs (bortezomib, gefitinib, imatinib) and with tamoxifen.
Are commercial Aloe vera gel products reliably pure?
Not always. Aloe vera gels are sometimes subject to harmless-seeming adulteration, such as dilution, addition of dextrins or other sugars and minerals, or use of whole leaves processed with activated charcoal instead of just the central parenchyma. Published monographs and certifications, mostly in the United States, only screen out the crudest forms of adulteration.
Primary Literature
Bibliography
↑1. Lavergne R. Les plantes médicinales Réunionnaises d'aujourd'hui. Éd. Orphie, 2008.
↑2. Yaron A. Characterization of Aloe vera gel before and after autodegradation, and stabilization of the natural fresh gel. Phytother Res. 1993;7(7):S11. DOI: 10.1002/ptr.2650070706 →
↑3. Zhang Y, Bao Z, Ye X, Xie Z, He K, Mergens B, Li W, Yatcilla M, Zheng Q. Chemical investigation of major constituents in Aloe vera leaves and several commercial aloe juice powders. J AOAC Int. 2018;101(6):1741-51. DOI: 10.5740/jaoacint.18-0122 →
↑4. Bozzi A, Perrin C, Austin S, Arce Vera F. Quality and authenticity of commercial aloe vera gel powders. Food Chem. 2007;103(1):22-30. DOI: 10.1016/j.foodchem.2006.05.061 →
↑5. Femenia A, Sánchez ES, Simal S, Rosselló C. Compositional features of polysaccharides from Aloe vera (Aloe barbadensis Miller) plant tissues. Carbohydr Polym. 1999;39(2):109-17. DOI: 10.1016/S0144-8617(98)00163-5 →
↑6. Personal communication. Cited regarding acetyl-glucomannan content variability.
↑7. Davis RH, Donato JJ, Hartman GM, Haas RC. Anti-inflammatory and wound healing activity of a growth substance in Aloe vera. J Am Podiatr Med Assoc. 1994 Feb;84(2):77-81. PubMed PMID:8169808 →
↑8. Udupa SL, Udupa AL, Kulkarni DR. Anti-inflammatory and wound healing properties of Aloe vera. Fitoterapia. 1994;65(2):141-145.
↑9. Benson KF, Newman RA, Jensen GS. Antioxidant, anti-inflammatory, anti-apoptotic, and skin regenerative properties of an Aloe vera-based extract of Nerium oleander leaves (nAE-8®). Clin Cosmet Investig Dermatol. 2015 May 6;8:239-48. PubMed PMID:26005354 →
↑10. Noor A, Gunasekaran S, Soosai Manickam A, Vijayalakshmi MA. Antidiabetic activity of Aloe vera and histology of organs in streptozotocin-induced diabetic rats. Current Science. 2008;94(8):1070-1076.
↑11. Davis RH, Maro NP. Aloe vera and gibberellin. Anti-inflammatory activity in diabetes. J Am Podiatr Med Assoc. 1989 Jan;79(1):24-6. PubMed PMID:2724102 →
↑12. Halder S, Mehta AK, Mediratta PK. Augmented humoral immune response and decreased cell-mediated immunity by Aloe vera in rats. Inflammopharmacology. 2012 Dec;20(6):343-6. PubMed PMID:22477034 →
↑13. Liu C, Leung MY, Koon JC, Zhu LF, Hui YZ, Yu B, Fung KP. Macrophage activation by polysaccharide biological response modifier isolated from Aloe vera L. var. chinensis (Haw.) Berg. Int Immunopharmacol. 2006 Nov;6(11):1634-41. PubMed PMID:16979117 →
↑14. Djeraba A, Quere P. In vivo macrophage activation in chickens with Acemannan, a complex carbohydrate extracted from Aloe vera. Int J Immunopharmacol. 2000 May;22(5):365-72. PubMed PMID:10708884 →
↑15. Kim HS, Kacew S, Lee BM. In vitro chemopreventive effects of plant polysaccharides (Aloe barbadensis miller, Lentinus edodes, Ganoderma lucidum and Coriolus versicolor). Carcinogenesis. 1999 Aug;20(8):1637-40. PubMed PMID:10426820 →
↑16. Metro D, Cernaro V, Papa M, Benvenga S. Marked improvement of thyroid function and autoimmunity by Aloe barbadensis miller juice in patients with subclinical hypothyroidism. J Clin Transl Endocrinol. 2018 Feb 14;11:18-25. PubMed PMID:29527506 →
↑17. Oryan A, Naeini AT, Nikahval B, Gorjian E. Effect of aqueous extract of Aloe vera on experimental cutaneous wound healing in rat. Veterinarski Arhiv. 2010;80(4):509-522.
↑18. Vázquez B, Avila G, Segura D, Escalante B. Antiinflammatory activity of extracts from Aloe vera gel. J Ethnopharmacol. 1996 Dec;55(1):69-75. PubMed PMID:9121170 →
↑19. Davis RH, Leitner MG, Russo JM, Byrne ME. Anti-inflammatory activity of Aloe vera against a spectrum of irritants. J Am Podiatr Med Assoc. 1989 Jun;79(6):263-76. PubMed PMID:2746485 →
↑20. Davis RH, Parker WL, Samson RT, Murdoch DP. The isolation of an active inhibitory system from an extract of aloe vera. J Am Podiatr Med Assoc. 1991 May;81(5):258-61. PubMed PMID:2061823 →
↑21. Reuter J, Jocher A, Stump J, Grossjohann B, Franke G, Schempp CM. Investigation of the anti-inflammatory potential of Aloe vera gel (97.5%) in the ultraviolet erythema test. Skin Pharmacol Physiol. 2008;21(2):106-10. PubMed PMID:18253066 →
↑22. Heggie S, Bryant GP, Tripcony L, Keller J, Rose P, Glendenning M, Heath J. A Phase III study on the efficacy of topical aloe vera gel on irradiated breast tissue. Cancer Nurs. 2002;25(6):442-451. PubMed PMID:12464836 →
↑23. Hoopfer D, Holloway C, Gabos Z, Alidrisi M, Chafe S, Krause B, Lees A, Mehta N, Tankel K, Strickland F, Hanson J, King C, Ghosh S, Severin D. Three-Arm Randomized Phase III Trial: Quality Aloe and Placebo Cream Versus Powder as Skin Treatment During Breast Cancer Radiation Therapy. Clin Breast Cancer. 2015;15(3):181-90.
↑24. Williams MS, Burk M, Loprinzi CL, Hill M, Schomberg PJ, Nearhood K, O'Fallon JR, Laurie JA, Shanahan TG, Moore RL, Urias RE, Kuske RR, Engel RE, Eggleston WD. Phase III double-blind evaluation of an aloe vera gel as a prophylactic agent for radiation-induced skin toxicity. Int J Radiat Oncol Biol Phys. 1996;36(2):345-349. PubMed PMID:8892458 →
↑25. Ajmera N, Chatterjee A, Goyal V. Aloe vera: Its effect on gingivitis. J Indian Soc Periodontol. 2013 Jul;17(4):435-8. PubMed PMID:24174720 →
↑26. Woźniak A, Paduch R. Aloe vera extract activity on human corneal cells. Pharm Biol. 2012 Feb;50(2):147-54. PubMed PMID:22338121 →
↑27. Langmead L, Feakins RM, Goldthorpe S, Holt H, Tsironi E, De Silva A, Jewell DP, Rampton DS. Randomized, double-blind, placebo-controlled trial of oral aloe vera gel for active ulcerative colitis. Aliment Pharmacol Ther. 2004 Apr 1;19(7):739-47. PubMed PMID:15043514 →
↑28. El-Gammal E, Nardo VD, Daaboul F, Tchernev G, Wollina U, Lotti J, Lotti T. Apitherapy as a New Approach in Treatment of Palmoplantar Psoriasis. Open Access Maced J Med Sci. 2018;6(6):1059-1061. PubMed PMID:29983801 →
↑29. Boudreau MD, Beland FA. An evaluation of the biological and toxicological properties of Aloe barbadensis (Miller), Aloe vera. J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2006 Apr;24(1):103-54. PubMed PMID:16690538 →
Additional Reference Literature
Clinical abstracts, Inflammation. Full Text →
Vogler BK, Ernst E. Aloe vera: a systematic review of its clinical effectiveness. Br J Gen Pract. 1999 Oct;49(447):823-8. PubMed PMID:10885091 →
Clinical abstracts, Wound Healing (Vulnerary effects of Aloe vera). Full Text →
Foster M, Hunter D, Samman S. Evaluation of the Nutritional and Metabolic Effects of Aloe vera. In: Benzie IFF, Wachtel-Galor S, editors. Herbal Medicine: Biomolecular and Clinical Aspects, 2nd ed. Boca Raton: CRC Press; 2011. Chapter 3. Full Text →