Mildly toxic — irritant
Mildly toxic. The gel inside is largely harmless, but the leaf’s outer layer (latex) contains compounds that cause vomiting and diarrhoea in dogs and cats. Best kept out of reach.
For pets the issue is the yellowish latex just under the skin of the leaf, which contains saponins and anthraquinones that irritate the gut and act as a laxative. The clear inner gel is much less of a problem, but a pet chewing a whole leaf gets the latex too. Reactions are usually unpleasant rather than life-threatening, but young, small or unwell pets can become quite poorly.
Both dogs and cats are affected, with similar gut-upset symptoms. Curious chewers and plant-nibbling cats are most at risk.
If your pet ate a small amount, watch for vomiting and diarrhoea and keep them hydrated; call your vet if symptoms are severe, persistent, or your pet is small or unwell. For a large amount, contact your vet or a poison helpline. Keep aloe plants up high, out of paw and jump range.
Related: Is snake plant toxic? · Is pothos toxic? · Is spider plant safe?
General information, not veterinary advice. If your pet has eaten a toxic plant or shows symptoms, contact your vet or a pet poison helpline immediately. Full disclaimer.