Aloe vera is a plant species of the genus Aloe.

It grows wild in tropical climates around the world and is cultivated for agricultural and medicinal uses.

Aloe is also used for decorative purposes and grows successfully indoors as a potted plant.

It is found in many consumer products including beverages, skin lotion, cosmetics, or ointments for minor burns and sunburns.

There is little scientific evidence of the effectiveness or safety of Aloe vera extracts for either cosmetic or medicinal purposes.

Studies finding positive evidence are frequently contradicted by other studies (source)

So can guinea pigs eat aloe?

They are very powerful plants and so it is not advisable to do so.

There are better plants to feed a piggie.