Why is my cat's poop black on antibiotics for mouth infection?

It isn't normal at all, black stools is usually a sign of bleeding from the upper gastrointestinal tract. That could be due to a stomach ulcer or pancreatitis for example. A severe infection could also cause this. If the black stools do not get better within 48 hours you will need to take him back to the vet in order to run some tests.

Thanks for using Petco Pet Education Center, formerly Petcoach! Since you are in day 1 of the antibiotics I think it would be fair to give it a bit more time to see if Musika gets better. You can try to entice his appetite with things like tuna, tuna water and chicken. If his appetite does not improve by tomorrow, let your veterinarian know as anorexia can be detrimental to a cat's health. Good luck and have a great day!

Thanks for using Petco Pet Education Center, formerly Petcoach! I want Mittens to get checked out but it's not an emergency. The fact that he is eating and acting normally is huge and a very good thing. It could be that his GI tract has just been very upset by the antibiotics. While you gather the money for a recheck appointment, try a probiotic like Purina FortiFlora (use as directed on the box). You can also add a fiber supplement like Benefiber powder (tasteless- 1 tsp with each meal). Stay on the GI diet given by your vet as this is likely also helpful. If this seems to fix the problem, great! If not, get into the vet as soon as you are able to get other medications for the diarrhea. Best of luck to you and Mittens!

The change is stool color is probably from the medication or new supplement. It doesn’t look like it is from blood from the photo. As long as he’s feeling fine finish the antibiotics and check the stool after they are done. It should go back to his normal stool color. If the dark stool continues then I recommend having it checked for occult blood and intestinal parasites. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Bruno.

I'm not sure what Panda is on antibiotics for, but I'm going to assume it was for issues with pooping. If they aren't improving things yet, it's time to ring the vet again and discuss other possible causes of these issues, including intestinal parasites and food intolerance.

There are a number of concerns here but the development of blacker stools can be indicative of internal bleeding and requires urgent veterinary assessment and a check up of kidney function and dental health (swallowed blood can be detected in stools). It sounds like she has also suffered from colitis and/or pancreatitis (soft, slimey, malodorous) in the past and diet change to a high fiber, low fat complete food may help depending on the findings of her physical exam and blood/urine tests

Hello. I am so sorry for your concerns with Momo. The dark color of the stool does not overly concern me as this can reflect something he has eaten, but with the diarrhea, it may be something inflammatory in his intestines, or even parasites. If he has not been wormed in a while, I would have your veterinarian check his stool just to make sure. If everything is OK, your veterinarian may make some recommendations to address the diarrhea, including the possible use of antibiotics, probiotics or a dietary change. Best to you & Momo & thanks for contacting Petco Pet Education Center, formerly Petcoach.