Having been shamed by NR's wonderful threads about looking after stray dogsI've decided to ask your help regarding this damn cat that wants to live in my house.

I cannot keep it out, i think it is quite old, a little blind and deaf, and has no where else to go.

I already have 2 cats, but they seem to tolerate this old cat.

But lately it was shit and pissed all over my house, vomiting too, i think. I always thought cats never did that?

I'm thinking of taking it to the vet to get a clean bill of health on it, or am I risking my other cats health doing this?