what is it? well basically its the stomach flu in laymans term, or
it means you will be praying in the bathroom for most of your day and
night. just be careful with what you eat. i ate some bad chicken
yesterday night. and geez i paid for it all night long. no no picture
today.
a more thorough description
http://en.wikipedia.org/wiki/Gastroenteritis
man you have to love that wikipedia.