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

Aloe vera

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.


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 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://ws.cam-cancer.org/The-Summaries/Herbal-products/Aloe-vera. March 20, 2013.


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  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.
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  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.
  20. Sakai R. Epidemiologic survey on lung cancer with respect to cigarette smoking and plant diet. Jpn J Cancer Res 1989; 80(6):513-520.
  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.