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Anna, Cat Expert, Biologist
Category: Cat
Satisfied Customers: 11061
Experience:  Thirty years of cat ownership. Writer for cat/pet magazines. B.A. in biology. Vet assistant.
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I noticed a dark, tarry, shiny substance on the blanket of

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I noticed a dark, tarry, shiny substance on the blanket of my cats' bed. There are also dark spray marks on the walls surrounding the bed. It doesn't seem like blood or stool. What is it?
Hello and welcome,

Thank you for requesting me. The only way to be sure of what the substance is would be to take a sample of it to your vet to be examined. However, a dark, tarry substance is exactly how stool with old blood in it is described. If a cat eats something bloody, or if there is bleeding, from the upper digestive system, the blood is partially digested before it is passed out, and it looks dark (almost black) in that state. If a cat also has some diarrhea, the stool may come out forcefully and uncontrollably wherever the cat happens to be. Vomiting old blood would be another possibility. It could easily end up on the wall. I know of no other substance that would come from a cat in such a way.

There won't be any way to know which cat it is from unless you see it happening. Sometimes a little bit may be left around the back end (if it's stool) or the mouth (if it's vomit), but most cats clean themselves too well for us to find such traces. I suggest getting a sample of the substance in a clean plastic bag. Keep it refrigerated until you can take it to the vet. As long as it doesn't happen again and the cats continue to behave normally, this isn't an emergency. I wouldn't even take a cat in since you don't know which one it was, but I would definitely take in a sample first thing in the morning for your vet. If any of the cats become lethargic, stop eating, or eliminate this substance again, you'll want to go to an emergency clinic.

Otherwise, take the sample to your vet, and once he/she determines exactly what it is, the vet will help you decide on the next step. If you have more questions, let me know in a REPLY. I hope all your cats will be just fine.


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