The queen of therapeutic plants: from soothing to healing properties

Editorial Note

This article was originally published in the past and has been updated according to scientific and divulgative criteria. The text summarizes currently available evidence on Aloe vera in an informative way and does not replace medical advice. For clinical clarifications, always consult a healthcare professional.

In brief

• Aloe vera contains a gel rich in polysaccharides (including acemannan), phenolic compounds, and small active ingredients that explain many biological properties.
• For skin and wounds, clinical evidence is heterogeneous: some studies suggest benefits for burns and local healing, but the quality of evidence remains limited.
• A controlled trial reported clinical improvement in ulcerative colitis after 4 weeks of oral gel, but the results require confirmation on a larger scale.
• Many observed activities (anti-inflammatory, antimicrobial, immunomodulatory) are supported by in vitro and animal research; clinical translation is incomplete.
• Safety warning: leaf parts containing aloin/anthraquinones can have laxative effects and reactions; choose clearly formulated and tested products.

Abstract: what does science say?

Aloe vera is a succulent plant whose inner gel has been used for centuries for topical applications and, in some cases, for oral use. Experimental evidence shows that aloe extracts contain immunomodulatory polysaccharides, antioxidant phenolic compounds, and molecules with antimicrobial activity that can promote biological processes involved in inflammatory response and tissue regeneration. However, controlled clinical studies are few and often of limited quality; systematic reviews report inconsistent results for wounds and moderate preliminary evidence for some intestinal conditions. The effect strongly depends on the form of extract (dewaxed inner gel vs. whole leaf extract), the concentration of active fractions, the route of administration, and the duration of treatment. Experimental data support biological plausibility, but causal clinical proof remains incomplete and requires larger, standardized trials. This summary is not intended to prescribe therapies but to offer a balanced evaluation of current knowledge.

The plant and its components

Aloe vera (Aloe barbadensis Miller) contains a complex set of polysaccharides (including acemannan), sugars, minerals, vitamins, organic acids, and phenolic compounds in its inner gel. The chemical quality of the gel varies by species, cultivation conditions, and extraction method. Detailed chemical characterization of polysaccharide fractions has allowed the identification of structures that explain immunomodulatory properties observed in the laboratory: the composition and degree of O-acetylation of mannans are correlated with biological activity. [4]

The review literature on acemannan summarizes anti-inflammatory, antibacterial activities, and properties that promote tissue regeneration in experimental models, but highlights methodological variability among studies and the need for standardized preparations to translate results into clinical practice. [3]

Composition and quality of preparations

Not all products labeled "aloe vera" are equivalent. Dewaxed and decolorized inner gel differs greatly from preparations that also contain the green part of the leaf (rich in anthraquinones like aloin). Recent analytical methods allow the characterization of polysaccharides, phenols, and anthraquinones, useful information for predicting efficacy and safety. [4] Accurate chemical characterization is a prerequisite for reproducible clinical studies.

Clinical evidence in dermatology and wounds

The topical use of aloe vera is among the most studied. Systematic reviews and Cochrane reviews highlight that available trials are few, with limited sample sizes and a risk of bias: some studies on superficial burns and surgical wounds have shown reductions in healing times, while others found no differences compared to standard comparisons. Overall, reviews conclude that the quality of evidence is insufficient to recommend routine use. [1]

For burns, specific reviews have found conflicting outcomes: some controlled studies suggested improvement, but the overall evidence remains limited by the variability of products used and outcome criteria. [6] Recent in vitro and biomimetic material research shows how phenolic and polysaccharide extracts can promote fibroblast proliferation, cell migration, and collagen synthesis in tissue repair phases, indicating mechanistic plausibility useful for the development of new dressing devices. [7]

Topical use: efficacy and context

Topical efficacy seems to depend on the clinical context (type of wound, thickness, presence of infection), the formulation (pure gel, creams, impregnated dressings), and product quality. Reviews recommend considering Aloe vera as a possible complement in some cases but not as a substitute for validated standard care; randomized studies with larger samples and standardized preparations are needed. [1][6][7]

Evidence for the digestive system

Oral use of aloe (inner gel) has been evaluated in some gastrointestinal conditions. A randomized, double-blind, placebo-controlled clinical trial observed clinical improvements in ulcerative colitis after oral gel administration for four weeks, suggesting a possible anti-inflammatory effect at the intestinal level. This result is interesting but remains a single study with limitations and requires independent and larger confirmations to establish long-term efficacy and safety. [2]

Other digestive applications cited in the literature (e.g., irritable bowel syndrome) show variable and inconclusive results; moreover, substantial differences are known between oral products regarding the content of anthraquinones, which can have undesirable laxative effects. Therefore, oral use requires caution and preferably medical supervision in chronic conditions.

Oral use: benefits and precautions

Oral administration can expose to compounds (e.g., aloin) with laxative activity and potential drug interactions. Documented benefits in trials are preliminary; the variability of preparations and the lack of long-term studies limit the generalization of indications. [2]

Plausible biological mechanisms

The biological plausibility of actions attributed to aloe vera is supported by experimental data: polysaccharides like acemannan appear to stimulate certain aspects of the immune response (macrophage activation, cytokine modulation) and promote fibroblast proliferation and collagen synthesis in cellular and animal models. [5][4] Phenolic compounds offer antioxidant and antimicrobial activity in in vitro experiments, while anthraquinones are responsible for the laxative effect and also have antimicrobial properties in an experimental setting. [3][8]

In summary, hypothesized mechanisms include local immune modulation, stimulation of cell migration and proliferation in the proliferative phase of repair, an antioxidant effect that reduces oxidative stress, and an antimicrobial component that can limit local bacterial load. However, the strength of these actions varies greatly with the composition of the preparation and the concentrations used in the laboratory are often higher than those achievable with some commercial products.

Laboratory evidence and clinical translation

Much evidence comes from in vitro or animal studies documenting effects on cytokines, cell proliferation, and antibacterial activity. These results justify targeted clinical studies but do not automatically imply clinical efficacy in human conditions: the transition from experimental models to well-designed trials is crucial to establish doses, formulations, and safety profiles. [5][7][3]

Safety and adverse effects

The safety of topical use is generally good for purified preparations; however, allergic skin reactions can occur. For oral intake, the presence of anthraquinones (aloin, aloe-emodin) in some products can cause laxative effects, cramps, and potential interactions. In experimental studies on anthraquinone-rich extracts, antimicrobial activity has been documented, but also the need to limit aloin concentration for safety reasons. [8]

Safety guidelines and regulatory reports recommend the use of standardized products that declare the absence or low content of aloin for oral use; in case of concomitant therapies or chronic medical conditions, it is advisable to consult a healthcare professional before using aloe-based supplements.

Key takeaways

• Aloe vera contains components with plausible anti-inflammatory, antimicrobial, and regenerative activity, but clinical translation is partial.
• For wounds and burns, clinical data are conflicting: some positive studies, but systematic reviews highlight methodological limitations. [1][6]
• A controlled trial showed improvement in ulcerative colitis with oral gel for 4 weeks, a result to be considered preliminary. [2]
• Product quality is crucial: different extracts and concentrations lead to different effects and safety profiles. [3][4]
• Beware of the presence of aloin/anthraquinones: possible laxative effects and risks from uncontrolled oral administration. [8]

Limitations of the evidence

Most positive results come from observational, experimental studies, or small trials; only a few good quality randomized clinical studies are available. It is essential to distinguish between: in vitro/animal observations (showing plausible mechanisms), small or heterogeneous clinical studies (suggesting possible effects), and robust causal evidence (required for clinical recommendations). [5][7][1]

Recurring methodological limitations include small samples, lack of standardization of preparations, non-homogeneous clinical outcomes, and risk of bias. The variability of the context (type of wound, severity of illness, preparation used) makes it difficult to generalize results; therefore, interpretations must be cautious and oriented towards further controlled and standardized studies.

Editorial conclusion

Aloe vera remains a plant with a long tradition of use and solid bases of biological plausibility on multiple fronts: immune modulation, antioxidant action, support for cell migration, and antimicrobial activity in the laboratory. However, the strength of clinical evidence is still insufficient for universal approvals or recommendations. In dermatological contexts and dressings, some local applications can be evaluated as a complementary option when using tested products; for oral use, especially in chronic conditions, the choice of preparation and medical supervision are essential. Future research should focus on randomized trials, standardized preparations, and studies that link dosages, chemical composition, and measurable clinical outcomes.

Editorial note

This update has been drafted with criteria of scientific rigor and institutional divulgative language (EFV). The sections cite verifiable studies (see bibliography with DOI). The article is for informational purposes and does not provide personalized therapeutic indications.

SCIENTIFIC RESEARCH

1. Dat AD, Poon F, Pham KB, Doust J. Aloe vera for treating acute and chronic wounds. Cochrane Database Syst Rev. 2012;2:CD008762. https://doi.org/10.1002/14651858.CD008762.pub2
2. Langmead L, Feakins RM, Goldthorpe S, Holt H, Tsironi E, De Silva A, Jewell D, Rampton DS. Randomized, double-blind, placebo-controlled trial of oral aloe vera gel for active ulcerative colitis. Aliment Pharmacol Ther. 2004;19:739-747. https://doi.org/10.1111/j.1365-2036.2004.01902.x
3. Sierra-García GD, Castro-Ríos R, González-Horta A, Lara-Arias J, Chávez-Montes A. Acemannan, a polysaccharide from Aloe vera: a review. Nat Prod Commun. 2014;9(8):1219-1226. https://doi.org/10.1177/1934578X1400900836
4. Tai-Nin Chow J, Williamson DA, Yates KM, Goux WJ. Chemical characterization of the immunomodulating polysaccharide of Aloe vera L. Carbohydr Res. 2005;340:1131-1142. https://doi.org/10.1016/j.carres.2005.02.016
5. Zhang L, Tizard IR. Activation of a mouse macrophage cell line by acemannan: the major carbohydrate fraction from Aloe vera gel. Immunopharmacology. 1996;35(2):119-128. https://doi.org/10.1016/S0162-3109(96)00135-X
6. Maenthaisong R, Chaiyakunapruk N, Niruntraporn S, Kongkaew C. The efficacy of Aloe vera used for burn wound healing: a systematic review. Burns. 2007;33(6):713-718. https://doi.org/10.1016/j.burns.2006.10.384
7. Iosageanu A, Mihai E, Seciu-Grama A-M, Utoiu E, Gaspar-Pintiliescu A, Gatea F, Cimpean A, Craciunescu O. In Vitro wound-healing potential of phenolic and polysaccharide extracts of Aloe vera gel. J Funct Biomater. 2024;15(9):266. https://doi.org/10.3390/jfb15090266
8. Forno-Bell N, Bucarey SA, García D, Iragüen D, Chacón O, San Martín B. Antimicrobial effects caused by Aloe barbadensis Miller on bacteria associated with mastitis in dairy cattle. Nat Prod Commun. 2019. https://doi.org/10.1177/1934578X19896670