The pre-existing clause is very sneaky. My cat had diarrhea 11 months before this visit. Diarrhea is symptom of an illness - Not the Diagnosis itself. The stool specimen tested negative at that time. A switch to a different food worked. Then as noted, 11 months later another episode of diarrhea. This time the cat had contracted Tritrichomonis Foetus. (a parasite) So a different illness completely. Petplan states the diarrhea is pre-existing - so would not pay the claim. Horrible.