
Blood in
the stool of cats and dogs can be caused by rectal irritation,
parasites, anal glands, or infections. Blood in the urine of cats and
dogs can be caused by bladder stones, cancers, urethritis, bladder
infections or urinary sand. If you only see a small amount of blood
once, and your cats seem fine, then you don't need to worry. If the
blood continues, worsens, becomes associated with mucus or foul odor,
or if your pets act sick, stop eating, or strain to urinate or
defecate, then you should arrange for a visit from your veterinarian
immediately.