Dolly has been vomiting infrequenty tinged with fresh blood and grass...help with thoughts of what t

Dolly, our probelm cat, has vomited once about a trace enough to stain the carpet with what appeared to be old blood (kind of coffee colored) and nothing else that we could see.  The next episode a day later was liquid with grass strands mixed with blood, enough that it stained the concrete.

She plays and eats well, no discoloration of gums or sensitivity.

Any thoughts from the group?

I would take her for a vet check.  That sort of vomit (coffee-ground) indicates bleeding, and cats are past masters at hiding being ill until they are very ill.