Written by Edzard Ernst and the CAM-Cancer Consortium.
Updated March 20, 2013

Aloe vera

Abstract and key points

  • Aloe vera is a cactus-like plant with a long history of medicinal use.
  • Aloe vera gel is applied topically and is used for radiation-induced skin problems. However, clinical trials show that it is ineffective for that purpose.
  • Aloe vera latex (juice) is taken orally. It has been insufficiently tested as a cancer therapy.
  • Oral use might cause abortion in pregnant women.

This summary is currently (April 2018) being updated, the version published here was last updated in March 2013. 

Aloe vera is a plant remedy used for a wide range of problems. In oncology, it is mostly advocated as a topical treatment to prevent or treat skin irritation after radiotherapy. The trial data, however, seem to indicate that it is ineffective for that purpose. Oral Aloe vera juice has been tested as a 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.

Read about the regulation, supervision and reimbursement of herbal medicine at NAFKAMs website CAM Regulation.

What is it?

Description

Aloe vera is a cactus-like plant with a long history of medicinal use.

Scientific name

Aloe vera, Aloe barbadensis.

Ingredients

Aloe vera gel which is made of the mucilaginous tissue from the centre of the Aloe vera leaf contains polysaccharides. Aloe vera latex (the form taken orally), which is made of the peripheral bundle sheath cells 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.

History

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.

Mechanisms of action

A multitude of potential mechanisms of action has been identified2. In vitro experiments have suggested that constituents of Aloe vera, such as aloin, exhibit anti-cancer effects through anti-angiogenic and cytotoxic activities3-5. Animal experiments have demonstrated detoxification of carcinogens,6 reduction of papilloma growth in mice7,8. and chemopreventive effects through modulating antioxidant and detoxification enzyme activity9.

Aloe vera latex is a powerful laxative. Aloe vera gel has antimicrobial, antioxidant, antiproliferative, chemo-preventive, anti-inflammatory, moisturising and antipuritic actions1,10,11. Anthraquinones of Aloe vera latex also have cytotoxic, radioprotective as well as antiangiogenic effects and inhibit angiogenic and metastatic regulatory processes12,13. In addition, aloin may Aloin enhance cisplatin antineoplastic activity in B16-F10 melanoma cells14. Whole leaf extract of Aloe vera has been shown in animal experiments to have carcinogenic potential 4.

Alleged indications

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. Precise prevalence figures are not available.

Legal issues

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.

Does it work?

This summary is currently (April 2016) being updated, the version published here was last updated in March 2013. 

Topical Aloe vera gel

Systematic reviews

Several clinical trials of topical Aloe vera gel to treat radiation-induced skin problems are available, and Richardson et al.10 have summarized their findings in a systematic review. The authors included seven RCTs. 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 therefore concluded 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”10.

A Cochrane review of various interventions to prevent mucositis in cancer patients included no further trials15. The authors did not draw a positive conclusion but felt that “there is a need for well-designed and conducted trials.”

Clinical trials

Since the publication of these reviews, several further trials have become available

Aloe vera gel was tested in an RCT with 57 head and neck cancer patients undergoing radiotherapy 16. The experimental group received topical aloe vera gel daily until one month after the completion of readiotherapy plus standard care; the control group had standard care only. The results demonstrated that there were a significantly delayed onset of skin reaction and low percentage of patients with severe radiotherapy induced skin reactions in the experimental group as compared to control group. At one month post radiotherapy there was no significant difference between two groups for radiotherapy induced skin reactions. During the later course of radiotherapy (at 6th /7th week) significant difference between two groups for pain scores was seen. However there was no significant difference in the two groups in the occurrence of radiation induced skin reaction related complications the authors conclude that aloe vera gel was effective in delaying the onset and reducing the severity of radiation induced skin reactions during the course of radiotherapy.

Another trial tested aloe vera gel for oral submucosal fibrosis (OSMF), a potentially malignant disorder of the oral mucosa, frequently associated with chewing gutka and betel quid 17. Twenty study subjects with OSMF were included in the study. Patients were randomised into two groups; group A received 5 mg of aloe vera gel to be applied topically three times daily for 3 months. Group B subjects received antioxidant capsules twice daily for 3 months. The results showed that aloe vera patients responded better in terms of symptoms and early-stage histopathology. Aloe vera generated a statistically significant relative reduction in burning sensation, improvement in mouth opening, and cheek flexibility.

Oral Aloe vera

Clinical trials

The effectiveness of oral Aloe vera products are less well studied. Lissoni et al.12 treated 50 patients with advanced mixed cancers either with melatonin or with melatonin plus Aloe vera tincture (1ml, 2x/day). A partial response was seen in no patient from the former and two patients from the latter group. These findings are preliminary at best.

Su et al.11 randomised 58 head and neck cancer patients to receive either Aloe vera (20ml juice) or placebo in addition to usual care. The results show no statistically significant inter-group differences in terms of quality of life, mucositis, pain, weight loss and other endpoints.

Lissoni et al.18 randomised 240 patients with mixed metastic solid tumours into receiving either chemotherapy or chemotherapy plus Aloe vera (extract of 300g fresh leaves 3x/day). The results indicated that tumour regression, 3-year survival times and subjective symptoms were both better in the latter group. This study seems well-conducted and its results are encouraging. However, independent replication seems necessary.

Puataweepong et al.19 conducted an RCT with 61 head and neck cancer patients who received either Aloe vera juice or placebo in addition to usual care. The endpoint was mucosal reaction to radiation therapy. The incidence of severe mucositis was 53% in the Aloe vera group and 87% in the placebo group. No difference was noted in the duration of mucositis, however.

The notion that oral Aloe vera might prevent lung cancer was supported by a Japanese case-control study20. 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.

Is it safe?

Adverse effects

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, diarrhoea, fluid and electrolyte loss.

Contraindications

Oral: pregnancy (oral administration can cause abortion), intestinal obstruction or inflammation.

Interactions

Oral: increased effects of antiarrhythmics, cardiac glycosides, diuretics and steroids2.

Warning

Based on animal studies, there is a suspicion that oral use of Aloe vera might promote colonic cancer21 and that topical use might enhance the induction of skin cancer by ultraviolet light22.

Citation

Edzard Ernst, CAM-Cancer Consortium. Aloe vera [online document]. http://cam-cancer.org/The-Summaries/Herbal-products/Aloe-vera. March 20, 2013.

Document history

Fully updated and revised in March 2013 by Edzard Ernst.
Summary first published in July 2011, authored by Edzard Ernst.

References

  1. Ernst E, Pittler MH, Wider B, Boddy K. The Desktop Guide to Complementary and Alternative Medicine. 2nd edition. Edinburgh: Elsevier Mosby. 2006.
  2. Ulbricht C, Armstrong J, Basch E, Basch S, Dacey C, Dalton S et al. An evidence-based systematic review of Aloe vera by the Natural Standard Research Collaboration. J Herb Pharmacother 2007; 7(3-4):279-323.
  3. Cárdenas C, Quesada AR, Medina MA. Evaluation of the anti-angiogenic effect of Aloe-emodin. Cell Mol Life Sci 2006; 63(24):3083-3089.
  4. 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 Oncol 2007; 43(9):905-910.
  5. 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 Biol Ther 2006; 5(1):97-103.
  6. Singh RP, Dhanalakshmi S, Rao AR. Chemomodulatory action of Aloe vera on the profiles of enzymes associated with carcinogen metabolism and antioxidant status regulation in mice. Phytomed 2000; 7(3):209-219.
  7. Saini M, Goyal PK, Chaudhary G. Anti-tumor activity of Aloe vera against DMBA/croton oil-induced skin papillomagenesis in Swiss albino mice. J Environ Pathol Toxicol Oncol 2010; 29(2):127-135.
  8. Chaudhary G, Saini MR, Goyal PK. Chemopreventive potential of Aloe vera against 7,12-dimethylbenz(a)anthracene induced skin papillomagenesis in mice. Integr Cancer Ther 2007; 6(4):405-412.
  9. 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. Curr Med CHem 2010; 17(2):129-138.
  10. Richardson J, Smith JE, McIntyre M, Thomas R, Pilkington K. Aloe vera for preventing radiation-induced skin reactions: a systematic literature review. Clin Oncol 2005; 17:478-484.
  11. 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. Int J Radiat Oncol Biol Phys 2004; 60:171-177.
  12. Lissoni P, Giana L, Zerbini S, Trabattoni P, Rovelli F. Biotherapy with the pineal immunomodulating hormone melatonin versus melatonin plus Aloe vera in untreatable advanced solid neoplasms. Nat Immun 1998; 16:27-33.
  13. 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. Eur J Pharm Sci 2012; 45(5):581-591.
  14. 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.
  15. Worthington HV, Clarkson JE, Bryan G, Furness S, Glenny AM, Littlewood A et al. Interventions for preventing oral mucositis for patients with cancer receiving treatment. Cochrane Database Syst Rev 2011;(4):CD000978.
  16. George J. To assess the effectiveness of aloe vera gel in preventing skin reactions associated with radiotherapy. Indian Journal of Palliative Care 2011; 17:91-103.
  17. Sudarshan R, Annigeri RG, Sree VG. Aloe vera in the treatment for oral submucous fibrosis - a preliminary study. J Oral Pathol Med 2012; 41(10):755-761.
  18. Lissoni P, Rovelli F, Brivio F, Zago R, Colciago M, Messina G et al. A randomized study of chemotharpy versus biochemotherapy with chemotherapy plus Aloe arborescens in patients with metastic cancer. In Vivo 2009; 23:171-176.
  19. Puataweepong P, Chanachai M, Dangprasert S, Sithatani C, Sawangsilp T, Narkwong L et al. The efficacy of oral Aloe vera juice for radiation induced mucositis in head and neck cancer patients: a double-blind placebo-controlled study. Asian Biomed 2009; 3(4):375-382.
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  21. Yokohira M, Matsuda Y, Suzuki S, Hosokawa K, Yamakawa K, Hashimoto N et al. Equivocal colonic carcinogenicity of Aloe arborescens Miller var. natalensis berger at high-dose level in a Wistar Hannover rat 2-y study. J Food Sci 2009; 74(2):T24-30.
  22. National Toxicology Program. Photocarcinogenesis Study of Aloe vera [CAS NO. 481-72-1(Aloe-emodin)] in SKH-1 Mice (Simulated Solar Light and Topical Application Study). Natl Toxicol Program Tech Rep Ser 2010; Sep(553):1-206.