Can Worms In Dogs Cause Diarrhea

Can Worms In Dogs Cause Diarrhea?

Last Updated: August 18, 2023
correct answerThe Short Answer is:

Parasites in the intestinal tract can cause diarrhea in dogs. If an animal has worms, it may not show any obvious signs, but diarrhea can be a sign of worms. Dogs can have bloody diarrhea or mucus in their stool depending on the severity of the infection.

In this article you will know the answer to the query “Can Worms In Dogs Cause Diarrhea?“.

The occurrence of canine diarrhea is always concerning for pet parents as its a sign that something is wrong. Its usually one of the first symptoms of many dog diseases including intestinal parasites to see your dog with diarrhea. 

Can Worms In Dogs Cause Diarrhea

There are several intestinal parasites that can infect dogs including roundworms hookworms whipworms and tapeworms and severe infections can be life-threatening for puppies and weak dogs. 

Because dogs can transmit worms to humans it is important to know how dogs get worms and to recognize the signs of worms in pets for timely treatment since worms are a problem for the entire family. 

1. Can Worm In Dogs Cause Diarrhea?

Parasites in the intestinal tract can cause diarrhea in dogs. If an animal has worms it may not show any obvious signs but diarrhea can be a sign of worms. Dogs can have bloody diarrhea or mucus in their stool depending on the severity of the infection. 

In the case of chronic heartworm infection blood in the stool and prolonged diarrhea may result in lethargy dehydration vomiting change in appetite and high blood pressure. In dogs intestinal parasites can cause life-threatening diseases especially prolonged infections in puppies and malnourished dogs which if left untreated can lead to death. 

Some dogs with worms do not show any visible signs of infection. Some worm larvae can lay dormant in a dogs system for a long time without the animal becoming ill. However they will eventually manifest during times of extreme stress for the dog. See your veterinarian immediately if you notice that your dogs stool has a tinge of blood or mucus.

2. What are the other symptoms or side effects of worms?

A severe infestation of canine worms can be deadly and immediate medical attention is needed. There are other symptoms of worms in dogs besides diarrhea that you can look for to determine if your dog has intestinal parasites; 

Coughing and vomiting

dog worm infestation symptoms. Heartworms will cause dry and persistent coughs because they infect the lungs and affect the respiratory system. In addition to coughing dogs with hookworms and roundworms may vomit visible worms. Yellowish green vomit is one of the symptoms of whipworm infection in dogs.

Intestinal worms

Intestinal worms steal nutrients from dogs’ intestines. Weight loss can be due to poor diet or other health problems but it can also be due to intestinal worms. Dogs that have tapeworms or whipworms lose weight rapidly.

Bloated belly

roundworm infestations are common in puppies with bloated bellies but it’s sometimes seen in adult dogs. The puppy can become infected with roundworms either while still growing in the mothers body or by ingesting breast milk from the mother.  

Dry and dull coat

A dull and dry coat with visible rashes is a sign of parasitic infections such as worms. Healthy dogs should have thick shiny coats. 


Dogs are deprived of nutrients when the worms consume their food which can cause them to feel lethargic and lack energy. 

Worms in feces

Some dogs will have visible worms in their stool due to a severe worm infestation. Roundworms and tapeworms appear as small moving rice-like specks in a dogs stool. It is also possible to find grain-like particles in the sleeping area or around the rear of the dog.  

Scratching or rubbing their rear

If your dog has worms in their rear they may feel itchy and as a result they may lick their paws scratch the floor or rub their paws against furniture.

3. How do dogs get worms?

Dogs can catch worms in different ways. They can nip or eat contaminated soil containing microscopic worm eggs eat infected meat or get them through their skin particularly their feet. Dogs can contract worms in many ways. 

From their mothers

if the mother dog is infected with roundworms or hookworms during pregnancy this can be passed down to her pups through the placenta which can then result in worms in the pups when they are born. When the puppies are nursing she can pass the bacteria to them by feeding them breast milk.

As a result of ingesting infected stool or soil

When dogs ingest soil or fecal matter containing microscopic larvae or eggs of intestinal worms these worms travel through their digestive tracts where they continue their development into adult parasites that feed off the dog.

By ingesting contaminated meat

When dogs hunt small prey like rodents or birds they tend to eat their kills. Dogs can become infected with parasites after consuming infected meat especially raw meat.

External parasites

fleas and tapeworms are parasites of the intestines that are carried by external parasites. In the event that a dog eats an infected flea the tapeworms in the flea are passed into the dog who becomes their new host. 

Through skin contact

If dogs walk on soil or stool contaminated with worms some worms such as hookworms can attach themselves to their paws and burrow into their skin causing infection.

4. Why do worms cause diarrhea?

When a dog becomes infested with worms these parasites travel through its bodies and settle in the intestines especially for roundworms hookworms tapeworms and whipworms. Usually these intestinal parasites reside in the hosts intestine where they feed on the hosts food. 

There are two types of worms that live in the digestive tract: roundworms live in the intestines and feed on their victims blood while whipworms live around the large and small intestines. Food that has been partially digested.

Hookworms also attach themselves to the lining of the intestinal walls where they extract nutrients to nourish themselves and tapeworms use their hook-like mouthparts to attach themselves to the walls of the small intestines to feed on digested food. 

They cause diarrhea bloody stools lethargy vomiting etc. when they extract nutrients from digested food. Veterinarians can see these worms during microscopic examination of stool samples when these worms are present in an infected dogs stool. 

5. What are the other causes of diarrhea?

Diarrhea in pets may be a sign that they have intestinal parasites but this isnot always the case. Dogs with normal bowel movements and solid stool may still have worms buried deep within them. Diarrhea is a symptom of unusually rapid bowel movements which are accompanied by improper absorption of water electrolytes and nutrients from digested food. 

Anemia is a common symptom of many dog illnesses such as bacterial or viral infections organ dysfunction intestinal worms stress food allergies dietary indiscretions among others. 

It is also possible to tell the underlying cause of dog diarrhea from the color and consistency of a dogs stool. If your dogs stool is soft or poor-quality that can be a sign that something is not right. 

Bloody stool may indicate intestinal worms black stool indicates bleeding internally orange stool indicates liver issues green stool or one with red streaks may indicate a gallbladder issue greasy or grey stool indicates a pancreas issue etc. 

6. How to cure diarrhea in dogs?

If your dog is experiencing diarrhea combined with other symptoms such as vomiting and lethargy you should take him to the nearest vet clinic and do not try any home treatments yourself.

However if your dog only has diarrhea and signs of vomiting you can try a conventional treatment like depriving him of food for 12 to 24 hours or giving him small amounts of food and water.

Dogs with diarrhea must drink plenty of water in order to prevent dehydration. 

How to help a dog with diarrhea; 

You should prepare a bland diet that consists only of easily digestible foods such as white rice wholemeal pasta porridge oats and boiled chicken or fish. Spices fats and dairy products are to be avoided. 

Your dog should be fed small portions at every meal. Feed them four to six times a day and monitor their stool quality. 

Try to gradually increase portions after diarrhea clears after a few days (2 to 3 days) and continue with the bland diet. Nevertheless if symptoms persist see a veterinarian as soon as possible. 


Dog diarrhea is due to many diseases but it can also be a sign of intestinal worms especially if it is accompanied by other symptoms such as blood in stool lethargy weight loss a pot-bellied appearance dull coat coughing vomiting and moving rice-like specks in stool. Dogs usually acquire worms through ingestion of infected substances or from their mother as puppies. When your dog exhibits diarrhea and any of the other symptoms listed above you should take him to the vet immediately. 

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Amanda Dogs Trainer

Amanda (Author)

With over a decade of experience, Amanda is a distinguished dog trainer. Her expertise in canine behavior has transformed countless lives, fostering harmonious human-canine connections. Through compassionate and personalized approaches, she empowers owners to understand and connect with their furry companions, creating a legacy of joyful tails and transformed lives.

Osvaldo Maciel Dogs Trainer

Osvaldo Maciel (Content Reviewer)

Osvaldo Maciel, a stalwart in the field with 14 years of experience, is a revered dog trainer. His journey is defined by a profound understanding of canine behavior, shaping unbreakable human-canine bonds. Osvaldo guides owners to connect with their beloved pets, leaving an indelible mark of happiness and transformation. His legacy shines through the countless lives he has touched.

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