This article is not for the squeamish! It’s a topic that many
pet parents wish they could avoid, but the reality is that
understanding the function of your dog’s anal sacs and the
potential complications is important.
The anal sacs -- also known as anal glands -- are two small
repositories located around your dog’s anus that continually
produce a foul-smelling substance. The odor of that substance
is what identifies your dog and marks their stool as a way to establish territory.
This is why rather than shaking paws when two dogs meet, they
smell each other’s rear ends.
Here we will review what you need to know about your dog’s anal
sacs and anal sac disease.
How Do Anal Sacs Work?
If looking at your dog’s anus straight on, the anal sacs are
located between the internal and external anal sphincter
muscles at 4 o’clock and 8 o’clock. The sacs are lined with
sebaceous glands (oil glands) and apocrine glands (sweat
glands) that produce a somewhat oily, brownish in color, and
awful smelling substance. The sacs are connected to the outside
by small ducts that open just inside of the anus.
The anal sacs are often emptied by the pressure caused by a
large, firm stool. They can also empty if a dog is afraid or
upset and responds with forceful sphincter contractions.
In some dogs, the glands do not empty regularly as they should,
which can lead to a blocked accumulation of secretions known as
Anal Sac Impaction: Causes, Symptoms, and Treatment
Anal sac impaction occurs when the sacs do not empty and
secretions accumulate. This can happen if a dog is passing soft
or small stools that do not create enough pressure to empty the
sacs. It can also occur as a result of anal sphincter muscle
dysfunction or if the openings of the anal sacs are blocked by
thick, semi-solid secretions (which, for unknown reasons, some
dogs are prone to producing).
If your dog’s anal sacs are impacted, they will be distended
and tender. In addition, your dog may “scoot,” chase their tail, and lick or
bite their rear end. Impactions are most common in small-breed dogs and overweight dogs, and if left untreated
can lead to infection, abscess, and ultimately rupture. This
whole cycle is what is referred to as anal sac disease.
Anal sac impaction is treated by manually expressing -- or
emptying -- the anal glands. Your veterinarian can do this or can show you
how to do it at home. If your dog has recurrent impactions, it
is a good idea to learn how to do it and manually empty the
sacs on a schedule set by your veterinarian. Your veterinarian
may also prescribe a high-fiber
diet to increase the size and firmness of your dog’s
How to Express Your Dog’s Anal Sacs
Sounds pleasant, doesn’t it? Once you get used to it, emptying
your dog’s anal sacs becomes just as routine as brushing their teeth or trimming their nails.
We’ll provide some instruction here, but you should consult your veterinarian before
attempting to express your dog’s anal sacs for the first
1. Put on latex or plastic surgical gloves. (Trust us: you
don’t want to get this substance on your hands!)
2. Raise your dog’s tail and locate the openings at 4 o’clock
and 8 o’clock.
3. If the anal sacs are full, they will feel like small, hard
4. Take the skin surrounding the sacs between your thumb and
forefinger and squeeze. If the anal sac is impacted, you may
need to put your forefinger inside of the anal canal and have
the thumb on the outside.
5. The secreted substance will smell very strong, and should be
liquid and brownish in color. If the substance is pus-like,
yellow, or bloody, the anal sacs may be infected, and you
should contact your veterinarian.
6. To clean up, wipe your dog’s rear end with a damp cloth or
spray with a hose.
Anal Sac Infection: Symptoms and Treatment
Anal sac infection is a potential complication of anal sac
impaction. The symptoms of an anal sac infection include
painful swelling of the anus, pus-like, yellow, or bloody
discharge, discomfort when defecating, and “scooting,” licking,
or biting the rear end.
An anal sac infection will be treated by your veterinarian.
They will manually empty the sacs and place an antibiotic
directly into the sac. They may also prescribe your dog with an
oral antibiotic. Dogs with recurrent anal sac infections
sometimes have their anal sacs surgically removed.
Anal Sac Abscess: Symptoms and Treatment
Anal sac abscesses can occur when there is a severe anal sac
infection. If your dog has an anal sac abscess, they will show
the same symptoms of anal sac infection and may also have a
fever. An abscess will begin as red and eventually turn
purplish, and may ultimately rupture through the skin. The
substance that comes out will likely be greenish yellow or
If you suspect that your dog has an abscess, you should
contact your veterinarian
right away. If the abscess has not already ruptured, your
veterinarian will be able to lance it, clean it, and then place
your dog on an oral antibiotic.
If the abscess has already ruptured, treatment is more
intensive and may include surgery to clean the sacs, removed
affect tissues, and place a drain to ensure that fluids drain
In these cases, your veterinarian may also suggest removing the
anal sacs at a later date.
Anal Sacs Problems In Dogs (And Cats)
The reason behind why some animals have anal sacs are still a
topic of wide debate. There has been much research into the
matter and many speculations. It’s a tricky area of your pet’s
body. They are also often known as anal glands although
technically they do not really have a glandular structure. Many
pet owners are concerned about the problems that might occur in
this undiscovered area of their pet’s body. The anal sacs
secrete an oily liquid-like substance which is stored inside
the sac.Most veterinarians and scientists still have no clue as
to why this liquid-like substance is excreted. You might find
yourself confused and concerned if your vet tells you that your
dog has a problem with his anal sacs. Anal sacs are likely to
be infected as it is located right next to the dirtiest part of
your dog’s body.
Treating Anal Sac
Anal tract infections are fairly easy to treat and diagnose.
Your vet will first examine your dog and if he finds a swollen
or inflamed spot next to your dog’s anus, he will then
recommend treatment. The infection causes an abscess that
appears on the dog’s skin. The abscess will look like it is
almost ready to pop or breakthrough. To treat this condition,
your vet will open the abscess in order to drain the infection
from the infected anal sac. He will then flush the sac and
check for infection in the other sac. If he finds that
everything is as it should be, he will put your dog on
antibiotics and simply send him home to rest.
What Exactly Are These Anal
There have only ever been theories as to why some animals
(cats, dogs, skunks etc.) have these sacs. One theory is that
the liquid-like substance that is secreted by these sacs along
with the stool acts as a territory marker due to its strong
smell. Not unlike how we humans hang up ‘No trespassing’ signs
to mark our property. Another theory is that the substance
that’s secreted by the anal sac makes the passage of the stool
easier by lubricating it. Just like how humans can get
hemorrhoids, dogs get anal sac infections.
What Causes The Problems
With The Anal Sac?
As the anal sac is an unusual body part, there aren’t specifics
to what causes the disorders. The dysfunction of the muscles of
the anal sphincter, sacs that appear enlarged due to
under-compression by the muscles of the anal sphincter,
hypersecretion of the liquid-like substance from the lining of
the anal sac, and ducts of the anal sac that may be obstructed
or constricted, are all predisposing circumstances that may
cause problems with the anal sac.
How Do You Tell If Your Pet
Has This Problem?
Only 12% of dogs experience disorders concerning the anal sac.
There is an 88% chance that you will never even hear the term
‘anal sac’ from your vet. But if you are part of the
unfortunate 12%, there are a few simple ways to recognize this
infection. If your dog shows any kind of discomfort while
passing stool or frequently turns and tries to bite his rear
end, you might want to make an appointment with your
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