Why Is There Mucus And Blood In Stool After Deworming?


All pet parents develop a sixth sense that makes them notice if there’s something odd about their dog’s stool.

This is especially true if you have a brand new puppy, quite adorable but also extremely vulnerable so you feel the need to be on the lookout constantly.

If there’s mucus and blood in your puppy’s stool you will certainly notice that, even if you don’t usually pay attention to your dog’s feces.

Is there cause of alarm if you see mucus or blood in the dog’s stool?

Probably not, but you need to understand how de-worming works, what to expect in the following days, and what’s normal or not.

Here is what you will learn from this article:

  1. How do dewormers work?
  2. Why might there be blood in the puppy’s stool after deworming?
  3. Why is there mucus in the puppy’s stool after deworming?
  4. When is mucus in the dog’s poop the sign of a problem?
    1. Intestinal parasites
    2. Stress
    3. Bacterial infection
    4. Inflammatory bowel disease
  5. How is excessive mucus diagnosed?
  6. What’s the treatment for excessive mucus in a puppy’s stool?
  7. Closing thoughts

How do dewormers work?

No matter how hard you try, it’s practically impossible to keep your dog from getting worms. Any dog will become infected with some type of worm at some point in his life.

The most common types of worms that can infect dogs include heartworms, roundworms, hookworms, tapeworms, coccidia and whipworms.

Heartworms are the most dangerous, but even those that are not life threatening can cause significant health issues. And it’s so easy for a dog to get infected.

Most worms are excreted through feces and they may stay in the soil even if the poop is removed and disposed of.

Dewormers work by killing or at least paralysing the worms long enough that the body can get rid of them. Whether you’re using a broad spectrum drug meant to eliminate all worms or medication designed to target specific parasites such as giardia or coccidia, the process is basically the same. 

Some drugs start showing results in as little as 2 hours, while others may take up to 12 hours to kill the parasites.

If you deworm your dog it is recommended to examine his feces, no matter how unpleasant that might be. Some parasites are very small and impossible to see with the naked eye, but others are big enough to be noticeable in the dog’s poop. Tapeworms are usually broken in smaller pieces, while others will be intact. And still alive after the paralysis effect wears off. You may notice worms in the dog’s stool for 1-2 weeks adn it’s nothing to worry about. It’s definitely gross, but at least it shows the medicine is working. 

Why might there be blood in the puppy’s stool after deworming?

Blood in the puppy’s stool is normal after deworming. What you may see in the feces is the blood that the parasites were feeding on. As they are killed and destroyed in the intestines the blood is released into the feces and passed unabsorbed. You shouldn’t be concerned unless you notice a lot of blood in the feces that might indicate another problem, that has nothing to do with the deworming process. Also, have a look at the color of the blood. If it’s bright red, this might indicate bleeding in the lower intestines and you should see a vet. 

Also, keep in mind that after deworming your dog, he shouldn’t have blood in the stool for more than a couple of days. If the problem persists, give your vet a call. 

Why is there mucus in the puppy’s stool after deworming?

Mucus is normal. The dog’s GI tract produces mucus to facilitate the elimination of feces. Most of the time you probably don’t even notice there’s some mucus in the puppy’s poop. After deworming the dog, it is possible to notice more mucus than normal and itself it’s nothing to worry about. What you should check is whether there are other signs your dog is unwell. Deworming drugs are quite strong and can cause various side-effects. It is important that you know what side-effects are normal after deworming.

The most common side-effects of dewormers include:

  • Vomiting 
  • Nausea
  • Diarrhea
  • Loss of appetite

If the dog vomits right after giving him the medicine, wait a few hours and give him another dose, this time with some food. 

Diarrhea can last for a few days and it’s most likely caused by the fact that the dog’s system is digesting the dead worms. 

If you have an elderly dog or one with a weakened immune system you should never deworm him without talking to the vet first as the medicine might put an additional strain on his liver and cause various health issues. 

One thing to keep in mind is that most dogs behave quite normally after deworming. Monitor your dog and see if he’s his normal self, interested in playing or going for a walk. If he seems up to his usual tricks, then there’s no need to be concerned about a little blood or mucus in his poop. 

When is mucus in the dog’s poop the sign of a problem?

While a little mucus is normal as the intestines need a bit of lubricant, too much mucus may be the sign of a problem. An isolated incident may not be a cause for concern, but if it becomes a regular thing you definitely need to have your pet checked out. 

If your dog’s GI tract produces an excessive amount of mucus this is usually a sign of colitis.

Colitis is an inflammation in the dog’s colon, which is the last segment of the intestinal tract. Excessive mucus is just one of the symptoms, so here’s what other things you should watch out for:

  • Abdominal pain
  • Diarrhea
  • Refusal to eat or drink
  • Only mucus coming out
  • Fever
  • Abnormally large stools

There are many reasons why your dog might get colitis. 

Intestinal parasites

Ironically, one of the main causes of excessive mucus production is worms. Then you have to deworm the dog and he might also show too much mucus in the stool. Giardia and whipworms are more likely to cause inflammation in the intestines.


Dogs can suffer from stress, too and this can lead to serious health issues, colitis being just one of them. Why would a dog be stressed? Dogs can suffer from both physical and mental stress. Physical stressors include strenuous exercise or undergoing a medical procedure. As for psychological stress, your dog might become anxious if there’s some change in the household, such as the arrival of a new baby or moving to a new house. If your pet is left at a boarding facility for a couple of days you can expect him to become anxious or depressed. He may not be able to tell you that, but if you notice changes in his bowel movements it might be stress colitis.

Dogs who are anxious by nature are more likely to develop colitis. It’s not a question of a certain breed being more susceptible to such problems, but age can be a factor. Young dogs are more likely to get stressed, so if your puppy shows signs of colitis try to analyze what psychological problems he might be having. 

Bacterial infection

While you’re worrying about worms, do not forget there are plenty of other dangers, including viruses and bacteria. One of the most common causes of bacterial colitis is infection with Salmonella or E.Coli. If you notice mucus in the puppy’s poop, think if there’s any chance he might have eaten something he shouldn’t have. Puppies are even more curious than adult dogs. They will stick their nose everywhere and taste whatever they find so dietary indiscretion is not to be ruled out. 

Inflammatory bowel disease

Inflammatory bowel disease is a syndrome characterized by chronic irritation in the GI tract and it can be caused by a variety of things, such as infections, allergies, parasites or genetic causes. 

How is excessive mucus diagnosed?

If you notice too much mucus in your dog’s poop more than once you should take him to the vet. However, the vet will want to see a stool sample, so you know what you have to do.

The doctor will start by asking you various questions to see whether the problem is caused by stress or dietary indiscretion. If there is no obvious cause, the vet will run various tests to check for parasites or bacteria. 

Also, the vet will try to see whether it’s mucus that’s coating the dog’s stool or it’s actual fat. This is a completely different problem and it’s usually a sign there’s too much fat in the dog’s diet, or he has an issue with the gallbladder or the pancreas.

What’s the treatment for excessive mucus in a puppy’s stool?

The treatment will depend on the underlying cause. If it’s parasites, he will recommend a dewormer. Bacterial infections usually require antibiotics, and your dog will ale need prebiotics to balance the microbiome. 

If your puppy has stress colitis, you will need to address the problem that’s making your dog miserable. Increased physical and mental stimulation can help dogs suffering from anxiety.

Also, your vet might recommend dietary changes, such as increased fiber intake which can help stool pass more easily and reduce inflammation. 

Closing thoughts

If your puppy was recently dewormed, blood and mucus in the stool may be a sign that the treatment is effective. The dog may eliminate parasites for up to 2 weeks, but if problems like blood and mucus in the stool are not resolved within a few days it might be best to see a vet. 

It may very well be that it’s just a coincidence and the excessive mucus in the feces is not related to the deworming medicine. It may be a sign of colitis, a common condition that can be triggered by a variety of factors. 

Sarah Pulsen

Hello, I have been in love with dogs since I was a little girl. I became even more infatuated with them when I was told by my Mum that I couldn't own one. Since I left home there has rarely been a time in my life when I have lived without a dog. My current dog is a Collie Terrier cross, called Ian.