- Aloe vera is a cactus-like plant with a long history of medicinal use.
- Evidence of Aloe vera gel/cream for radiation-induced skin problems is inconclusive.
- Topical Aloe vera appears as effective as conventional treatment for some symptoms in chemotherapy-/radiation-induced oral mucositis/stomatitis but the evidence is not convincing.
- Aloe vera gel may improve symptoms of oral submucosal fibrosis but evidence is poor quality.
- Topical Aloe vera may improve some symptoms of radiotherapy-induced proctitis, compared to placebo.
- Orally administered Aloe vera latex (juice) has been insufficiently tested as a cancer therapy.
- Adverse events are generally mild and transient but oral use might cause abortion in pregnant women.
Aloe vera, Aloe barbadensisis a plant remedy used for a wide range of problems. In oncology, Aloe vera is applied topically for radiation-induced skin problems, oral submucosal fibrosis (a precancerous condition) and chemotherapy-/radiation-induced inflammation of the digestive tract.
One systematic review (n=7) and four additional randomized controlled trials (RCTs) of Aloe vera for radiation-induced skin problems have conflicting results and many limitations. Moderate evidence from four RCTs suggests that Aloe vera mouthwash is as beneficial as conventional mouthwash for radiation-induced oral mucositis in head and neck cancer and chemotherapy-induced stomatitis in leukaemia. Although topical Aloe vera has shown some positive results for oral submucosal fibrosis compared to other treatment, these findings are limited by the methodological limitations of the trials. Evidence from one randomized clinical trial suggests Aloe vera ointment improves some symptoms of radiotherapy-induced proctitis compared to placebo. Oral Aloe vera juice has been tested as anti-cancer treatment, but studies are too preliminary to tell whether it is effective.
Numerous adverse events are on record but they are generally mild and reversible. Oral use might cause abortion.
Fully updated and revised in September 2018 by Ava Lorenc
Fully updated and revised in March 2013 by Edzard Ernst.
Summary first published in July 2011, authored by Edzard Ernst.
Ava Lorenc, Edzard Ernst, CAM-Cancer Consortium. Aloe vera [online document], http://cam-cancer.org/en/aloe-vera. September 18, 2018.
Aloe vera is a cactus-like plant with a long history of medicinal use.
Aloe vera, Aloe barbadensis.
Aloe vera gel is the mucilaginous tissue from the centre of the Aloe ver aleaf and contains polysaccharides. Aloe vera latex (taken orally), is made of the peripheral bundle sheath cells and contains aloin, anthraquinones, barbaloine and glycosides1.
Application and dosage
Gel is applied topically as needed. Latex is taken orally at doses between 50 and 200mg daily1.
Aloe vera has been used medicinally in many medical cultures. Today it is available as over-the-counter products and used by a range of healthcare professionals e.g. doctors, nurses, herbalists, naturopaths, nutritionists.
Claims of efficacy
Traditionally, Aloe vera has been used for a very wide range of conditions. In oncology, the main claim is that topical application of the gel prevents or treats radiation-induced skin reactions2.
The notion that oral Aloe vera might prevent lung cancer was supported by a Japanese case-control study3. A comparison of 44 pairs was analysed according to plant food intake. The results suggested that those study participants regularly consuming Aloe vera were associated with a reduced lung cancer-risk. Even though interesting, this small study cannot prove that the detected association is causal.
Mechanisms of action
A multitude of potential mechanisms of action has been identified by in vitro experiments2. Aloe perryiflowers inhibit the growth of seven cancer cell lines4 and Aloe vera extract inhibits the growth of breast, cervical cancer and neuroblastoma cells, and increases the therapeutic efficacy of conventional drugs5,6. Regarding the constituents of Aloe vera, aloin/barbaloin exhibits anti-cancer effects through anti-angiogenic and cytotoxic activities7-10, and aloe emodin inhibits the proliferation of cancer cells (including gastric, cervical, and lung cancers, glioma and melanoma)11-15, induces the expression of genes involved in apoptosis16, induces cell differentiation12, inhibits cancer metastasis17 and enhances the effect of radiation18 and tamoxifen19. Photodynamic therapy with aloe-emodin causes cell death, induces autophagy, and inhibits adhesion, migration and invasion of cancer cells14,20,21. Animal experiments have demonstrated detoxification of carcinogens22, reduced tumour angiogenesis23 and reduction of papilloma growth in mice24,25. and chemopreventive effects13,26,27 through modulating antioxidant and detoxification enzyme activity28.
Aloe vera latex is a powerful laxative. Aloe vera gel has antimicrobial, antioxidant, antiproliferative, chemo-preventive, anti-inflammatory, moisturising and antipuritic actions1,29,30. Anthraquinones of Aloe vera latex also have cytotoxic, radioprotective as well as anti angiogenic effects and inhibit angiogenic and metastatic regulatory processes31,32. In addition, aloin may enhance cisplatin antineoplastic activity in B16-F10 melanoma cells33. Whole leaf extract of Aloe vera has been shown in animal experiments to have carcinogenic potential8.
Aloin-loaded tablets may be a useful drug delivery system as a coadjuvant of conventional chemotherapy/radiation therapy34.
In oncology, the main indication for Aloe vera is the application of the gel for radiation-induced skin irritation, as well as to prevent or treat cancer
Prevalence of use
Generally speaking, Aloe vera products are very popular, particularly for self-treatment and for cosmetic use. Most healthcare professionals caring for cancer patients are aware of the claim that Aloe vera gel reduces skin inflammation, and many recommend it to their patients. In the general population, Aloe vera is used by between 7 and 10% of adults in Australia, Italy, and Jamaica. In the USA, dietary supplements containing Aloe vera were used by 0.1% of adults in the past 30 days, and Aloe vera is the 20th best-selling dietary supplement, with sales of US$72million in 201135.
Aloe vera products are sold as cosmetics or as herbal supplements.
Cost and expenditure
High quality products are widely available and usually inexpensive. A typical week’s supply of Aloe vera gel would cost less than €6.
Radiation-induced skin problems
Richardson et al’s 2005 systematic review29 included seven randomized controlled trials (RCTs) of topical Aloe vera gel to treat radiation-induced skin problems. The quality of the studies and of reporting was frequently poor. Overall, the results failed to show the superiority of topical Aloe vera gel over various control treatments. The authors conclude that “there is no evidence from clinical trials to suggest that topical Aloe vera is effective in preventing or minimising radiation-induced skin reactions in cancer patients”29.
Since the publication of this review, four further trials of topical Aloe vera on radiation-induced skin problems have become available (see Table 1)36-39. As highlighted by Richardson et al29, study quality and reporting are often poor. Topical Aloe vera may reduce the incidence of radiation-induced dermatitis in patients (n=60) with head and neck cancer36 although the study does have some limitations. One good quality (n=248) and one poor quality study (n=100) suggest no effect in breast cancer37,38. Haddad et al39 conclude that topical Aloe vera lotion reduces the intensity of radiation-induced dermatitis in various cancers (n=60), but their study is poor quality.
A 2011 Cochrane review of interventions to prevent mucositis in cancer patients included no further trials40. The authors did not draw a positive conclusion but felt that “there is a need for well-designed and conducted trials.”
Three subsequently published RCTs studied Aloe vera for radiation-induced oral mucositis in head and neck cancer (see Table 1)30,41,42, and one studied chemotherapy-induced stomatitis in patients with leukaemia43. There is moderate quality evidence that oral Aloe vera reduces the incidence but not duration of mucositis compared to placebo (n=61)41, and may reduce onset, severity, intensity and pain better than or as well as conventional mouthwashes (n=26, n=64)42,43. However, Su et al (n=58)30 found no difference compared to placebo.
Oral Submucosal Fibrosis (OSMF)
Four trials tested Aloe vera for oral submucosal fibrosis (OSMF), three topical (gel) (n=20), (n=120), (n=40)44-46 and one oral and topical (n=74)47 (see Table 1). OSMF is a potentially malignant disorder of the oral mucosa, frequently associated with chewing gutka and betel quid44. There was some evidence that Aloe vera may improve symptoms (burning sensation, mouth opening, tongue protrusion and cheek flexibility) as well as conventional treatment, but all four trials have significant limitations in methodology and reporting.
Based on one small RCT (n=20), topical Aloe vera appears to improve some symptoms of radiotherapy-induced proctitis (diarrhoea, faecal urgency, clinical presentation and lifestyle), compared to placebo48.
There is preliminary evidence from two RCTs (n=240) that Aloe vera in combination with chemotherapy (n=240)49 or melatonin (n=50)31 may improve stabilization of disease and survival in patients with advanced solid tumours, for whom no other standard effective therapy is available.
Numerous adverse effects are on record but, generally speaking, these are mild and reversible2. Topical use: allergic reactions, delayed healing of deep wounds.
Oral use: irritation of and damage to intestinal mucosa, intestinal pain, vomiting, diarrhoea, cathartic colon, fluid and electrolyte loss, kidney failure, phototoxicity and hypersensitive reactions50.
Oral: pregnancy (oral administration can cause abortion), intestinal obstruction or inflammation.
Oral: increased effects of antiarrhythmics, cardiac glycosides, diuretics and steroids2.
Based on animal studies, there is a suspicion that oral use of Aloe vera might promote colonic cancer51,52 although a subsequent study using Aloe vera extract with the latex component removed (which removed some mutagenic components53) had no toxicological findings after 13 weeks54. There is also suspicion that topical use might enhance the induction of skin cancer by ultraviolet light55.
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- Ulbricht C, Armstrong J, Basch E, Basch S, Bent S, Dacey C, et al. An evidence-based systematic review of Aloe vera by the natural standard research collaboration. Journal of herbal pharmacotherapy. 2007;7(3-4):279-323.
- Sakai R. Epidemiologic survey on lung cancer with respect to cigarette smoking and plant diet. Japanese journal of cancer research : Gann. 1989;80(6):513-20.
- Al-Oqail MM, El-Shaibany A, Al-Jassas E, Al-Sheddi ES, Al-Massarani SM, Farshori NN. In vitro anti-proliferative activities of Aloe perryi flowers extract on human liver, colon, breast, lung, prostate and epithelial cancer cell lines. Pakistan journal of pharmaceutical sciences. 2016;29(2 Suppl):723-9.
- Hussain A, Sharma C, Khan S, Shah K, Haque S. Aloe vera inhibits proliferation of human breast and cervical cancer cells and acts synergistically with cisplatin. Asian Pacific journal of cancer prevention : APJCP. 2015;16(7):2939-46.
- Yonehara A, Tanaka Y, Kulkeaw K, Era T, Nakanishi Y, Sugiyama D. Aloe vera Extract Suppresses Proliferation of Neuroblastoma Cells In Vitro. Anticancer research. 2015;35(8):4479-85.
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- Xiao B, Guo J, Liu D, Zhang S. Aloe-emodin induces in vitro G2/M arrest and alkaline phosphatase activation in human oral cancer KB cells. Oral oncology. 2007;43(9):905-10.
- Esmat AY, Tomasetto C, Rio MC. Cytotoxicity of a natural anthraquinone (Aloin) against human breast cancer cell lines with and without ErbB-2: topoisomerase IIalpha coamplification. Cancer biology & therapy. 2006;5(1):97-103.
- Wang YR, Yang SY, Chen GX, Wei P. Barbaloin loaded polydopamine-polylactide-TPGS (PLA-TPGS) nanoparticles against gastric cancer as a targeted drug delivery system: Studies in vitro and in vivo. Biochemical and biophysical research communications. 2018;499(1):8-16.
- Wu YY, Zhang JH, Gao JH, Li YS. Aloe-emodin (AE) nanoparticles suppresses proliferation and induces apoptosis in human lung squamous carcinoma via ROS generation in vitro and in vivo. Biochemical and biophysical research communications. 2017;490(3):601-7.
- Tabolacci C, Cordella M, Turcano L, Rossi S, Lentini A, Mariotti S, et al. Aloe-emodin exerts a potent anticancer and immunomodulatory activity on BRAF-mutated human melanoma cells. European journal of pharmacology. 2015;762:283-92.
- Chihara T, Shimpo K, Beppu H, Yamamoto N, Kaneko T, Wakamatsu K, et al. Effects of Aloe-emodin and Emodin on Proliferation of the MKN45 Human Gastric Cancer Cell Line. Asian Pacific journal of cancer prevention : APJCP. 2015;16(9):3887-91.
- Ismail S, Haris K, Abdul Ghani AR, Abdullah JM, Johan MF, Mohamed Yusoff AA. Enhanced induction of cell cycle arrest and apoptosis via the mitochondrial membrane potential disruption in human U87 malignant glioma cells by aloe emodin. Journal of Asian natural products research. 2013;15(9):1003-12.
- Trybus W, Krol T, Trybus E, Stachurska A, Kopacz-Bednarska A, Krol G. Induction of Mitotic Catastrophe in Human Cervical Cancer Cells After Administration of Aloe-emodin. Anticancer research. 2018;38(4):2037-44.
- Haris K, Ismail S, Idris Z, Abdullah JM, Yusoff AA. Expression profile of genes modulated by Aloe emodin in human U87 glioblastoma cells. Asian Pacific journal of cancer prevention : APJCP. 2014;15(11):4499-505.
- Ma JW, Hung CM, Lin YC, Ho CT, Kao JY, Way TD. Aloe-emodin inhibits HER-2 expression through the downregulation of Y-box binding protein-1 in HER-2-overexpressing human breast cancer cells. Oncotarget. 2016;7(37):58915-30.
- Luo J, Yuan Y, Chang P, Li D, Liu Z, Qu Y. Combination of aloe-emodin with radiation enhances radiation effects and improves differentiation in human cervical cancer cells. Molecular medicine reports. 2014;10(2):731-6.
- Tseng HS, Wang YF, Tzeng YM, Chen DR, Liao YF, Chiu HY, et al. Aloe-Emodin Enhances Tamoxifen Cytotoxicity by Suppressing Ras/ERK and PI3K/mTOR in Breast Cancer Cells. The American journal of Chinese medicine. 2017;45(2):337-50.
- Li KT, Chen Q, Wang DW, Duan QQ, Tian S, He JW, et al. Mitochondrial pathway and endoplasmic reticulum stress participate in the photosensitizing effectiveness of AE-PDT in MG63 cells. Cancer medicine. 2016;5(11):3186-93.
- Tu P, Huang Q, Ou Y, Du X, Li K, Tao Y, et al. Aloe-emodin-mediated photodynamic therapy induces autophagy and apoptosis in human osteosarcoma cell line MG63 through the ROS/JNK signaling pathway. Oncology reports. 2016;35(6):3209-15.
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- Kocik J, Balan BJ, Zdanowski R, Jung L, Skopinska-Rozewska E, Skopinski P. Feeding mice with Aloe vera gel diminishes L-1 sarcoma-induced early neovascular response and tumor growth. Central-European journal of immunology. 2014;39(1):14-8.
- Chaudhary G, Saini MR, Goyal PK. Chemopreventive potential of Aloe vera against 7,12-dimethylbenz(a)anthracene induced skin papillomagenesis in mice. Integrative cancer therapies. 2007;6(4):405-12.
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- Im SA, Kim JW, Kim HS, Park CS, Shin E, Do SG, et al. Prevention of azoxymethane/dextran sodium sulfate-induced mouse colon carcinogenesis by processed Aloe vera gel. International immunopharmacology. 2016;40:428-35.
- Shimpo K, Chihara T, Kaneko T, Beppu H, Wakamatsu K, Shinzato M, et al. Inhibitory effects of low-dose aloe-emodin on the development of colorectal tumors in min mice. Asian Pacific journal of cancer prevention : APJCP. 2014;15(14):5587-92.
- El-Shemy HA, Aboul-Soud MA, Nassr-Allah AA, Aboul-Enein KM, Kabash A, Yagi A. Antitumor properties and modulation of antioxidant enzymes' activity by Aloe vera leaf active principles isolated via supercritical carbon dioxide extraction. Current medicinal chemistry. 2010;17(2):129-38.
- Richardson J, Smith JE, McIntyre M, Thomas R, Pilkington K. Aloe Vera for Preventing Radiation-induced Skin Reactions: A Systematic Literature Review. Clinical Oncology. 2005;17(6):478-84.
- Su CK, Mehta V, Ravikumar L, Shah R, Pinto H, Halpern J, et al. Phase II double-blind randomized study comparing oral aloe vera versus placebo to prevent radiation-related mucositis in patients with head-and-neck neoplasms. International Journal of Radiation Oncology • Biology • Physics. 2004;60(1):171-7.
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- Suboj P, Babykutty S, Valiyaparambil Gopi DR, Nair RS, Srinivas P, Gopala S. Aloe emodin inhibits colon cancer cell migration/angiogenesis by downregulating MMP-2/9, RhoB and VEGF via reduced DNA binding activity of NF-kappaB. European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences. 2012;45(5):581-91.
- Tabolacci C, Rossi S, Lentini A, Provenzano B, Turcano L, Facchiano F, et al. Aloin enhances cisplatin antineoplastic activity in B16-F10 melanoma cells by transglutaminase-induced differentiation. Amino acids. 2013;44(1):293-300.
- De Caro V, Scaturro AL, Di Prima G, Avellone G, Sutera FM, Di Fede O, et al. Aloin delivery on buccal mucosa: ex vivo studies and design of a new locoregional dosing system. Drug development and industrial pharmacy. 2014;41(9):1541-7.
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- Ahmadloo N, Kadkhodaei B, Omidvari S, Mosalaei A, Ansari M, Nasrollahi H, et al. Lack of Prophylactic Effects of Aloe Vera Gel on Radiation Induced Dermatitis in Breast Cancer Patients. Asian Pacific journal of cancer prevention : APJCP. 2017;18(4):1139-43.
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