Aloe Vera Side Effects: Dangers and Contraindications
Aloe vera is everywhere — soothing gel, detox juice, cosmetics — but a large US toxicology study identified a specific risk that is essential to put in context, without unnecessary alarm.
Does aloe vera cause side effects? The purified gel used in cosmetics and most common food products has an excellent safety profile. The most serious point of concern involves a specific form of the plant: non-decolorized whole-leaf extract, which contains the latex (the yellow layer under the rind), for which a large US toxicology study identified a carcinogenicity signal in animals. This article explains that distinction precisely.
For aloe vera's uses, see our page aloe vera; general precautions are covered in aloe vera dangers.
What the reference study shows
In 2013, the US National Toxicology Program (NTP) published Technical Report 577, from a two-year toxicology and carcinogenesis study in rats and mice. The animals received non-decolorized whole-leaf Aloe vera extract in their drinking water (see the report on Google Scholar). Result: a significantly increased incidence of tumors (adenomas and carcinomas) of the large intestine in rats at the highest doses, with no equivalent effect seen in mice. This study led the International Agency for Research on Cancer (IARC) to classify non-decolorized whole-leaf extract as possibly carcinogenic to humans (Group 2B).
The essential distinction: whole leaf vs. purified gel
| Form | Contains latex (aloin)? | Safety status |
|---|---|---|
| Non-decolorized whole-leaf extract (tested by the NTP) | Yes | Classified possibly carcinogenic (Group 2B) based on the animal study |
| Purified, decolorized, filtered gel (common cosmetic and food use) | No, or greatly reduced traces | Not covered by this classification; very favorable safety profile |
In the vast majority of commercial products (soothing gel, cream, filtered "decolorized" juice), the latex and aloin have been removed during purification. That purification step is what makes the safety difference.
Practical precautions
- Unfiltered or "whole-leaf" aloe vera juice: avoid regular, prolonged consumption as a precaution, especially over the long term.
- Pure aloe vera latex (the yellow part): a powerful laxative effect due to aloin content; internal use should not be undertaken without guidance, particularly during pregnancy (possible reflex uterine-stimulating effect), in children, and with inflammatory bowel disease.
- Purified gel on the skin: very well tolerated in the vast majority of cases, with the risk mainly limited to possible contact allergy in sensitive individuals.
- Choosing a product: favor juices or gels that explicitly mention decolorization/filtration (controlled aloin content, generally under 10 ppm per industry standards).
What this means in practice
This study does not mean everyday use of aloe vera gel is dangerous: it specifically concerns unpurified whole-leaf extract, consumed in large quantities over the long term in animals. It nonetheless justifies avoiding prolonged consumption of unfiltered "whole-leaf" juice, and reserving pure latex for occasional, supervised use. General guidance is covered in our guide to choosing an Ayurvedic supplement and our safety and precautions guide.
Your questions about aloe vera side effects
Is aloe vera carcinogenic?
A US toxicology study found an increased risk of large-intestine tumors in rats exposed to high doses of non-decolorized whole-leaf extract. The purified gel used in most commercial products, without the latex, is not covered by this classification.
What is the difference between aloe vera gel and latex?
The gel is the clear central part of the leaf, well tolerated. The latex is the yellow layer under the rind, rich in aloin, a powerful laxative compound that is removed during the purification of commercial products.
Can you drink aloe vera juice every day without risk?
A properly decolorized/filtered juice, with controlled aloin content, is generally well tolerated with occasional use. Prolonged consumption of unfiltered "whole-leaf" juice is discouraged as a precaution.
Is aloe vera gel on the skin safe?
Yes, in the vast majority of cases. The risk is essentially limited to possible contact allergy in sensitive individuals, best tested on a small area before wider application.
Can a pregnant woman use aloe vera?
Purified gel used on the skin generally poses no issue. Aloe vera latex or juice taken internally is discouraged during pregnancy, however, as a precaution linked to its stimulating laxative effect.
What does IARC Group 2B classification mean?
It is a classification of possible carcinogenicity to humans, here based on an animal study using high doses of whole-leaf extract. It does not mean certain risk to humans at ordinary use, but it does justify caution for this specific form of the product.
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