18 year old cat peeing blood and vomiting. Probably stomatitis, take it to the vet it will only get worse. I am now distraught and depressed that I didn't get him to the vets sooner. Philadelphia, PA; Years ago my persian Female was diagnosed with FUS. It sounds like Hyperthyroidism or Kidney Disease. She vomits regularly but never blood until today. Has Symptoms Vomit loss of appetite blood in urine. The term cystitis does not imply a specific cause.