a friend of mine has it. what is it and what does it do to the person?

Chrohn's Disease is a painful miserable illness that has to do with the digestive system and the elimination process.

Here is a site with specifics.

Here is some more information on Crohn's Disease.

Looks like from the information that Sherasi gave it is hard to diagnose this disease. How did your friend find out they have it?

i don't know how she was diagnoised, she just said she has it.