Okay,

My question is this:

Why is human solid waste (feces) green when one is sick? Is there some kind of green bacteria thriving in the waste? I know this is a wierd question, but I'm sincerely interested.

No, I really don't think so.

Digestion determines the colour of your feces, an excess in iron is able to turn them green, anticoagulants turn them red, alcohols can turn them black. I'd say the chances are the illness is interfering with the digestion, e.g. by preventing absorption of iron, leading to it being expelled.

cool. thanks.