- Aloe gel
- aloe leaf
For Patients & Caregivers
How It Works
Aloe is safe for topical use. It is not an effective cancer treatment and is dangerous when given by injection.
Scientists think that compounds found in aloe inhibit molecules that play a role in inflammation. Studies in laboratory rats confirm this anti-inflammatory activity. Aloe is also thought to hinder the formation of thromboxane, a molecule that is detrimental to the healing of burn wounds. Aloe kills bacteria and fungi directly in laboratory studies. Aloe gel should not be confused with aloe juice or aloe latex, both of which contain potent laxative substances.
To treat burns
Scientific evidence supports the topical use of aloe for minor burns.
To prevent and treat redness, rash, and pruritus caused by radiation therapy
Clinical trials have produced conflicting results in support of and against this use. Topical use of aloe is generally safe.
To prevent oral mucositis caused by chemotherapy
There is evidence that aloe, when combined with chemotherapy, may prevent oral mucositis.
As a skin moisturizer
No scientific evidence supports this use.
To treat inflammation associated with conditions such as cold sores, eczema, and pruritis
Clinical evidence supports this use.
To treat cancer
No scientific evidence supports this use. Cancer therapy using injections of acemannan, a substance found in aloe, resulted in death of several patients.
To treat diabetes
Two non-randomized trials conducted by the same group suggest that blood glucose levels may be reduced by aloe vera. Further study is warranted.
To treat ulcerative colitis
A small randomized, controlled trial shows weak support for this use. More research is needed.
- Aloe gel should not be confused with aloe juice or aloe latex, both of which contain anthraquinone, a potent laxative.
- Despite the use of some oral dosages in clinical trials of ulcerative colitis, there is not enough evidence at this time to support the use of aloe vera by mouth or by injection. The risk of serious adverse effects is high, and several cancer patients died from aloe vera injections that were used as a cancer therapy.
Do Not Take If
- If you are taking drugs that are substrates of Cytochrome P450 3A4 and CYP2D6: Aloe vera juice may increase the risk of side effects of these drugs. Clinical relevance is not known.
- If you are taking sevoflurane: A case report showed that additive antiplatelet effects with aloe resulting in excessive bleeding during surgery.
- Certain dosages of aloe, when taken orally, can cause GI upset, nausea, vomiting, and rash.
- Toxicity from ingestion of aloe includes seizures, dangerously low blood potassium levels, and electrolyte abnormalities.
- A case of hypokalemia (low potassium levels) has been reported with use of aloe vera during chemotherapy.
- Three cases of toxic hepatitis (liver inflammation) were reported following use of aloe preparations. Liver function was normalized after discontinuing aloe.
For Healthcare Professionals
Aloe vera is a perennial, succulent plant that resembles a cactus and is used in traditional medicine throughout the world. The clear thick gel obtained from aloe leaves is used for wound healing, to treat burns, psoriasis, frostbite, ulcerative colitis, diabetes and to relieve constipation. Aloe demonstrated antioxidant and anti-inflammatory properties, in vitro (9).
In clinical studies, an Aloe vera cream was reported to be superior to silver sulfadiazine creams for the treatment of second-degree burns (21); an aloe gel was shown effective in skin graft donor-site healing (38); an aloe ointment improved symptoms of acute radiation proctitis in patients receiving radiotherapy (39); and an aloe cream improved postoperative pain and discomfort, and promoted healing following pilonidal sinus excision (45). A mouthwash containing aloe was shown to reduce plaque, gingivitis and S. mutans in the oral cavity in children, with the effects being comparable to chlorhexidine (46). Systematic reviews indicate aloe’s effectiveness against oral lichen planus, while not causing any adverse effects compared to corticosteroids (37); and for reducing pain/burning sensation and affecting clinical improvement in patients with oral submucous fibrosis (41). In addition, aloe gel complex was shown to affect reductions in body weight and insulin resistance in obese individuals with pre-diabetes or early untreated diabetes mellitus (29); to prevent pressure ulcers in hospitalized orthopedic patients at risk of developing such ulcers (42); to prevent traumatic oral ulceration in patients with fixed orthodontic appliances (47); and to accelerate split-thickness skin graft donor-site healing (43).
Data also suggest that constituents of aloe, such as acemannan, aloeride, and di(2-ethylhexyl)phthalate (DEHP) have immunomodulating and anticancer effects (5) (7) (8) (34) (35). Emodin from aloe inhibited cell proliferation and induced apoptosis in human liver cancer cell lines through p53- and p21-dependent pathways (4); along with enhancing the effects of radiation treatment (30). Concurrent administration of aloe with chemotherapy may prevent oral mucositis in patients receiving chemotherapy (23); along with benefitting those with metastatic cancers (20). However, findings of external use of aloe products to alleviate radiation-induced skin damage are inconsistent (1) (2) (3) (32) (36) (44).
Mechanism of Action
Several studies have been conducted to explore the mechanisms of action of aloe.
Oligosaccharides isolated from aloe extracts were found to prevent ultraviolet radiation-induced suppression of delayed type hypersensitivity by reducing keratinocyte-derived immunosuppressive cytokines (25). Proposed mechanism underlying anti-psoriatic effect includes inhibition of tumor necrosis factor (TNF)‑alpha‑induced proliferation of keratinocytes and overactivation of the nuclear factor (NF‑kappa B signaling pathway, by an aloe polysaccharide (40). And a polymer fraction of aloe was shown to protect the gastric mucosa against ethanol-induced gastric damage by decreasing mRNA expression levels of inducible nitric oxide synthase (iNOS), neuronal nitric oxide synthase (nNOS), and matrix metalloproteinase (MMP-9). The three enzymes are critical biomarkers in gastric ulceration (26). Other findings suggest that the radio-protective effects of aloe polysaccharides are most likely due to inhibition of apoptosis (27).
Emodin, an extract of Aloe vera, was shown to inhibit cell proliferation and induce apoptosis in human liver cancer cell lines through p53- and p21-dependent pathways (4). Acemannan, a carbohydrate fraction derived from Aloe vera leaf, was found to stimulate cytokine production in mouse macrophage cell line (5). It also exhibited immunomodulating activity by inducing maturation of dendritic cells (6). And aloeride, a polysaccharide obtained from aloe vera juice, was reported to be a potent immunostimulator that acts by enhancing NF-kappa B activities (7). In addition, di(2-ethylhexyl)phthalate (DEHP), isolated from Aloe vera, inhibited leukemic cells, in vitro (8).
Aloe gel should not be confused with aloe juice or aloe latex, both of which contain anthraquinone, a cathartic laxative. Aloe taken for internal use should be discouraged due to possible adverse effects and inconclusive clinical data. Aloe injections for cancer patients have resulted in several deaths.
The FDA rules that aloe is not safe as a stimulant laxative.
- Topical administration of aloe gel is considered safe but oral consumption of aloe can cause gastrointestinal upset and electrolyte abnormalities.
- Inappropriate use of aloe supplements has been linked to thyroid dysfunction (10), acute hepatitis (11), and perioperative bleeding (12).
- A case of hypokalemia has been reported with use of aloe vera during chemotherapy (19).
- Three cases of toxic hepatitis were reported following use of aloe preparations. Liver function was normalized after discontinuing aloe (22).
- Long term exposure to Aloe vera can cause cancer in animals (28) .
- Positive re-exposure tests have been reported with aloe, which highlight the herb’s potential for inducing liver injury (33).
- Cytochrome P450 substrates: In vitro, aloe juice was found to inhibit CYP3A4 and CYP2D6 and can affect the intracellular concentration of drugs metabolized by these enzymes (24). Clinical relevance is not known.
- Sevoflurane: A case report showed that additive antiplatelet effects with aloe resulting in excessive bleeding during surgery (12).