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Dr. Lisa
Dr. Lisa, Dog Veterinarian
Category: Dog Veterinary
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Experience:  10 years emergency/critical care vet, holistic veterinarian
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My dog has bloody mucus in her stool

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My dog has bloody mucus in her stool, sometimes this is all that comes out, what could be causing this? When this happens she is very out of it, not playful, very clingy to me, and after she passes the bloody mucus she seems to go back to normal.

She has also developed a lump at the bottom of her spine near her rear end, on top of her back. I have brought her to the vet for the bloody mucus and they put her on 3 antibiotics but it did not help.

I am scared to bring her to the vet because I don't want her to become a guinea pig. Can you shed some light on what might be the problem?

Thank you!!

P.S. She also eats wood, could there be a blockage? She has had an x-ray for this before.


I share your concern about your pet. How old is your dog? Does she have a history of prior illness? Is the lump on her back soft or firm? Has your veterinarian evaluated that yet?

Bloody mucus in the stool is caused by what is known as large bowel diarrhea or an inflammation of the colon. If the blood is bright red vs. dark red, this is confirmation that the irritation or inflammation is coming from the colon and not the stomach.

The condition is unlikely to be caused by a blockage since you have no symptoms of vomiting and your dog seems to be able to pass stool. But, it can very easily be caused by a dietary indiscretion (like eating wood). It can also be caused by Inflammatory Bowel Disease or a host of other issues like parasites (has your vet done a fecal exam?).

Her behavior change prior to the episodes seem to indicate that she has abdominal pain which is relieved by voiding the stool.

For starters, I would add fiber to your dog's diet. You can try canned pumpkin or metamucil (1 tsp/day) to see if that helps the situation. If it's not resolving, ask your vet to do a fecal exam. You can also try a home cooked diet for your pet to see if that improves the situation.

A good resource for home cooked diets for pets is Dr. Pitcairn's Complete Guide to Natural Health for Dogs and Cats, available at your library or book store.

In general, if your dog is not losing weight, vomiting or continually uncomfortable, this is not considered an emergency and you have the time to try a few things before you go back to your vet.

I hope that this is helpful. Please let me know if I can answer any questions.

Customer: replied 11 years ago.

Thank you. My dog is 2 1/2 years old, she is a 7 pound mini doxie. She does not have a history of prior illness. This has been going on for about 7 months. She has an episode about once a week, sometimes the episodes come once every couple of weeks.

The lump on her back seems to be pretty firm, to me that is. The vet has not checked the lump yet, I just noticed it yesterday and I was going to give it a little time to hopefully go away before I brought her in for it. When she passes this bloody mucus it is kind of dark red, you have to get close to it to realize that it is not diarrhea but actually a pile of just blood and mucus. She does vomit every so often, it is usually clear but yesterday it looked like dark applesauce. She still passes her regular stools daily.

She started this about 7 months ago when she had to live outside at my mom's house for a little while. I thought maybe she had been bit by a bug but it has continued for so long. She did come in contact with another puppy for 2 weeks and this is when these episodes started to happen, I actually thought it was this puppy, but it was my dog instead.

I have 2 other dogs and they were all together and they do not have any problems. She is on a strict diet of Nutro brand lamb and rice, she does not get any table foods. I was thinking maybe she has heart worms but I don't know what the symptoms are and am hoping that is not the case.

Thank you so much!!

The symptoms you describe are not related to heartworms. That is a respiratory condition, not a gastrointestinal one. Dark red blood is much more of a concern - it indicates bleeding somewhere higher up in the gastrointestinal tract. If she has intermittent vomiting, that is also a concern too. I would doubt that this is a bug bite of toxicity.

Here's what I would ask your vet to do:

1. Fecal exam - often parasites are the most common cause of vomiting and diarrhea in young dogs.

2. Change to a home made diet as recommended in the prior post. Cottage cheese and rice would work as well.

3. Blood panel - to look for cause of underlying disease.

4. Abdominal x-rays - to rule out foreign body or other problem.

I would NOT use additional antibiotics. There is no indication for this.

I hope that I've been helpful. If I have, please accept my answer. It helps us both!

Please let me know if you have additional questions.

Lisa Boyer, DVM

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