Aloe Vera is really quite an incredible plant. It is a succulent plant and part of the lily family (Liliaceae), the same family that garlic and onions belong to. Aloe Vera contains over 200 active components including vitamins, minerals, amino acids, enzymes, polysaccharide, and fatty acids- no wonder it's used for such a wide range of remedies. The bulk of the Aloe Vera leaf is filled with a clear gel-like substance, which is approximately 99% water.
You can keep an aloe vera leaf for 10 to 15 days at room temperature or from 20 to 25 days in the refrigerator (however it is better to be consumed as soon as possible). It's easy to extract gel:
Wash the aloe leaf. Using a sharp knife, peel along one of the spiked sides of the leaf.
Use the knife to slice the leaf open along that same side so that the leaf is cut in two along its length.
Use a clean spoon to scrape the gel from the leaf into a clean container.
The gel extracted degrades quickly - best to use it immediately but it should be OK for 3-4 days in the fridge.