Aloe vera
As you discovered, do not ingest the rind of the aloe. It contains an addictive laxative called Aloin, which is no longer considered safe.
The inner leaf gel of a properly grown Aloe vera barbadensis plant is totally safe, and the acemannan it contains is amazingly effective at immune support, glucose balance and stomach health. The problem is, most processes destroy the acemannan, leaving only a very expensive, low-quality Aloe food.
Currently the best Aloe product on the market is BiAloe(R). It contains from 4 to 10 times more bioavailable acemannan than any other product.
You can learn about the healing aspects of Aloe from the book "The
Science Behind Aloe: The Healing Plant" by noted medical researcher Dr. Bill McAnalley. You can learn about BiAloe(R) from AloeVnWell.com.
FYI I am affiliated with BiAloe(R)... (and they are looking for more affiliates. It is NOT MLM.)