There are many differences but a parasite can kill you as well, getting into your brain, blood, and organs.That's why you have to have a balance in your gut..all diseases start there... and antibiotics kill off all your good flora..I was surprised to find out that doctors in Colorado are telling patients to take probiotics while they're taking antibiotics, but about 2 hours apart...makes sense to keep your good flora going..even if you have to kill it off with the antibiotics daily..and when your done with the round of antibiotics it's critical to continue to take the probiotics...