I spoke too soon!

I told a friend that my 4 year old male cat had never thrown up. He threw up for the first time last night. Boy did he! By the look of the litter box he had diarrhea also. Is there a chance this might be a one time thing! He is very healthy and strictly indoors. I did feed him some canned food his sister would not eat. Could it have been bad? It was Felidae chicken and rice!

If he's not used to eating that particular food, it could've been too rich for his system and that caused things to go awry.  How is he otherwise?  Has he eaten anything yet?  Is he lethargic or normal activity level?

He is his good old evil self this morning. He ate all his breakfast and bit me hard, broke skin in 4 places. That is normal. He is a former feral that should have been put down but I could not do it. I threw the second can away, just in case. This is the bad boy, who never learned good behavior since he was abandoned as an infant.

If there are no further episodes with the vomiting and diarrhea, then I suspect the food was just too rich for his system.

Sorry you got bitten.  Be sure to take care of that wound.  Cat bites can be pretty dangerous.