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What is Biting His Tail?

At first you think your dog is being silly chasing his tail but then you realize he is biting and gnawing at the area. You try to deter him, but he goes right back to biting his tail.  There are several reasons why your dog is biting and chewing at his tail such as:

  • Impacted anal glands
  • Allergies
  • External parasites
  • Internal parasites
  • Poor hygiene
  • Injured tailbone
  • Behavior issues

If your dog is excessively biting on his tail, it may be an indication of a serious condition.

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Why Biting His Tail Occurs in Dogs

Impacted Anal Glands

Anal glands (anal sacs) are located on both sides of your dog’s anus. The glands produce a strong smelling fluid which is used for territorial marking. Normally, when your dog defecates it puts pressure on the glands, which causes the sacs to secrete onto the feces. If the fluid is not being expressed, the anal glands can get clogged and impacted. Impacted glands can be caused by the dog having soft stools which do not put pressure on the anal glands. The impacted glands cause the dog great discomfort.  He will bite and chew at his tail area.  Your dog may also scoot his bottom area on the floor.  The anal glands can also become infected and abscess.


Allergies may be making your dog very itchy and causing him to bite at his tail.  Allergies may be caused by diet or by environmental allergens. The most common food allergens are beef, dairy, corn, wheat and soy. Environmental allergens may include mold/mildew, and tree, grass and weed pollen.

External Parasites

Fleas, ticks and mites can cause great irritation and discomfort. Many dogs and cats are also allergic to the flea’s saliva, which causes the animal to experience severe itching.

Internal Parasites

Tapeworms and roundworms can cause your dog’s anus to be irritated. Tapeworms can be transmitted by a flea bite or by the dog ingesting a flea, which is carrying tapeworm eggs. Roundworms are more common in puppies.  Roundworms can be transmitted to humans by contact with contaminated stool or soil.

Poor Hygiene

Poor hygiene may be making your dog’s anal area itchy. The hair around the anus can get matted and have fecal matter (fecal mats).  This can cause the dog’s skin to get irritated and infected.  The fecal mats can also attract flies and cause a maggot infestation on your dog.

Injured Tail

A dog’s tail may be injured causing a fracture, dislocation, abrasion or laceration.  Dogs with long tails are more at risk of injuries.  An injured tail can cause a lot of pain.

Behavior Issues

Your dog may be biting at his tail due to behavior issues.  Dogs that are stressed or anxious may bite, gnaw or lick at their skin. A new pet or person in the household, fireworks, or a household move can cause a dog a great deal of stress.

What to do if your Dog is Biting His Tail

A dog that is excessively biting at his tail should be seen by a veterinarian.  A veterinarian can exam your dog and run a few diagnostic tests, which will help find the underlying cause of the tail biting.

Impacted glands will be expressed by the veterinarian.  Gland abscesses may need to be lanced. Your dog will be prescribed antibiotics and pain medication.  An Elizabethan collar will need to be worn to prevent the dog from biting or licking at the area.

Allergies may be treated with a change of diet or daily allergy shots. Dogs with external parasites will be treated with a flea and tick preventative medication. Internal parasites are treated with a dewormer medication.  The medication is administered orally or by injection.

If x-rays confirm a fractured tail, the dog’s tail may need to be splinted. Tail abrasions or lacerations will need to be cleaned and treated with antibiotic ointment.  The tail will be bandaged and your dog will have to wear an Elizabethan collar.

Dogs with behavior issues may be referred to an animal behaviorist. An animal behaviorist can observe your dog and make recommendations, which will help with bouts of stress and/or anxiety.

Prevention of Biting His Tail

A diet that is high in fiber may help prevent a loose stool.  The harder stool will put more pressure on the glands and help them to secrete.

Having your dog on a flea and tick monthly preventative can prevent external parasites. Internal parasites may be prevented by regular deworming. Puppies need to be dewormed at 2, 4, 6, 8 and 12 weeks of age. Adult dogs should be dewormed twice a year. 

Proper hygiene and regular grooming can help prevent matted hair and infections. 

Dogs should not be left unattended with small children.  Children sometimes can pull or step on a dog’s tail.  Hurting the dog may cause the dog to bite. To prevent an injury to the dog or to the child, the pair should not be left unsupervised.

Cost of Biting His Tail

Treatment costs of anal gland disorders may range from $75 to $500. Food allergies therapy may cost up to $1500.  Medicinal care to eliminate tapeworm or roundworm may range from $250 to $300.

Biting His Tail Questions and Advice from Veterinary Professionals

German Shepherd
12 Years
Serious condition
0 found helpful
Serious condition

Has Symptoms


I have a 12 yoa German Shepherd mix. I noticed last night a raw place after seeing a drop of blood on the floor. This morning, it is significantly worse, at least 2 inches of her tail that's a bald bloody mess! I'm beside myself as her vet can't get her in today and I'm waiting for the emergency vet to open. I'm afraid she may be stress chewing, if that's even a thing, as we brought home a 3 month old kitten on Saturday. We had 6 cats when we adopted her at 5, so she has been around cats before, although we haven't had any in several years.

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3317 Recommendations
It is possible that Lena is stress chewing or there is another cause for the chewing like parasites or another cause of irritation; if you have a cone to put on her in the meantime to prevent further biting it would be useful, plus bathing the wound with a dilute antiseptic. You should get into a Veterinarian as soon as possible for an examination. Regards Dr Callum Turner DVM

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toy poodle
7 Weeks
Mild condition
0 found helpful
Mild condition

Has Symptoms


I adopted a puppy age 6 weeks old now she is 7 weeks old. She is toy poodle. I noticed that she bites her legs and she scratches her ears and neck. she always lick her private areas. In the past two days she started chasing her tail aggressively and trying to bite it. I did take her outside for 6 days and she is only vaccinated one time. Since i knew that its not safe to have my puppy out without full vaccination i stopped taking her out. I am scared she got any type of virus or worms. please help. IN addition to that i noticed that she cries a little when she poops.

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3317 Recommendations
It is important to make sure that you complete her vaccinations before taking her outside as many cases of infectious diseases can be easily prevented with vaccination. However, it sounds like Nala may have either external parasites, allergies among other causes; without examining her I cannot say for certain but you should ensure that Nala has received worm treatment (anthelmintic) and a topical spot on flea & tick prevention applicable for her age and weight. You should visit your Veterinarian for an examination to check about the biting and the painful defecation; a little plain canned pumpkin in the food may help with defecation. Regards Dr Callum Turner DVM

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Australian Shepherd
5 Years
Moderate condition
0 found helpful
Moderate condition

Has Symptoms


Constant biting/licking under base of tale until raw ...we have to keep cone on him all the time....Aussie/blue healer mix 5 years old...this has been going on for years...comes and goes...had anal glands removed 3 years it allergies or a habit

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3317 Recommendations
Without examining Rocky it i difficult to say whether the cause is due to allergies, infection, parasite, behaviour defecation issues among other causes; if the biting comes and goes you should think about checking whether or not there are any triggers like food, certain treats, cleaning products, time of year etc… which may cause this biting. Normally a behavioural issue would be constant whereas allergies may be intermittent. Regards Dr Callum Turner DVM

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