Written by Edzard Ernst and the CAM-Cancer Consortium.
Updated July 26, 2011

Aloe vera

Does it work ?

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 7 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 review16 of all interventions to prevent mucositis in cancer patients included no further trials. The authors did not draw a positive conclusion but felt that “there is a need for well-designed and conducted trials”16.

Clinical trials

The effectiveness of oral Aloe vera products are less well studied. Lissoni et al.11 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.12 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.13 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.14 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 study15. 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.

Pre-clinical studies

In vitro experiments have suggested that constituents of Aloe vera, such as aloin, exhibit anti-cancer effects through anti-angiogenic and cytotoxic activities3,4,5. Animal experiments have demonstrated detoxification of carcinogens6, reduction of papilloma growth in mice7,8 and chemopreventive effects through modulating antioxidant and detoxification enzyme activity9.

Citation

Edzard Ernst, CAM-Cancer Consortium. Aloe vera [online document]. http://www.cam-cancer.org/CAM-Summaries/Herbal-products/Aloe-vera. July 26, 2011.

Document history

Next update due in autumn 2012.
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. 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.
  12. 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.
  13. 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.
  14. 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.
  15. Sakai R. Epidemiologic survey on lung cancer with respect to cigarette smoking and plant diet. Jpn J Cancer Res 1989; 80(6):513-520.
  16. Worthington HV, Clarkson JE, Eden TOB. Interventions for preventing oral mucositis for patients with cancer receiving treatment (review). Cochrane Database of Syst Rev 2008; 4(DOI: 10.1002/14651858 CD000978 pub3).
  17. 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.
  18. 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.
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