If there are large unwanted guests present, you may see them in your bowel movements. Microscopic unwanted guests, however, are invisible to the naked eye and you can never actually see them in your bowel movements.
It is also possible that you will not see anything, or experience any signs. This is quite common. You still may be a host to unwanted guests. These are creatures that specialize in living below your radar to ensure their survival. That is why it is so important to do a parasite cleanse, at least yearly, and take nothing for granted.