Anal Sacs

Pete Wedderburn
12th December 2019 - 5 min read

Signs Of Anal Sac Disease:

1.         “Scooting” or dragging the anal area along the ground.

2.         Excessive licking under the tail.

3.         Pain around the base of the tail

4.         A swollen, reddened area beside the anus.

5.         Bloody drainage on either side of the anus.

boxer sitting on ground
Pug Scooting

“Scooting”, or rubbing the rear end along the ground is a common behaviour shown by dogs. People often think that it is caused by worms. It is true that there are worms that can cause irritation under the tail, and it does make sense to check that a recent worm dose has been given. But the most common cause of the problem is a “dog” thing that thankfully, humans don’t suffer from anal sac disease.

What Are Anal Sacs?

Dogs, cats, and many other animals have two small anal sacs that produce a strong-smelling glandular secretion. The sacs, one on the left and one on the right, are hidden beneath the skin, at a position best described as “4 o’clock” and “8 o’clock”. Each sac is each connected by a duct to the lower bowel, just inside the anus. Every time the animal passes a motion, the anal sac is physically squeezed out, so that the secretion is applied to the outside of the faecal pellets. The anal sac secretion smells disgusting to humans, but it carries very important messages in the animal world.

Animal Territories

The concept of “territory” is an essential part of animals’ social lives, and anal sac scent deposits are one of the ways that pets leave a mark to let other animals know that they have been around. 

poodle tail
Poodle Tail – Side View

Diseased Anal Sacs

Occasionally, for different reasons, the anal sacs can become diseased, and the scooting behaviour is the most obvious sign that something has gone wrong. The problem is almost unique to dogs: although cats have anal sacs, they very rarely cause problems.


The most common problem in dogs is simple: the anal sacs stop emptying properly, and become over-full. They are normally around the size of a raisin, but they can expand to the size of a large grape. There are different reasons why they may not empty properly, but the most common one is that:

  • Modern pet food is not bulky enough to enable the sacs to be squeezed out effectively.
black dog eating dog food
Dog Eating Modern Pet Food
  • In the wild, dogs eat fur, skin, bones, and all sorts of other non-digestible matter that passes straight through their digestive system. As a result, their faecal pellets tend to be large, with a firm consistency, and they are very effective at squeezing out the anal sacs. Pet dogs tend to eat highly processed food that creates softer, smaller faecal pellets that are not as good at emptying the anal sacs. 

Why Do Dogs Scoot?

In most dogs, the low bulk of faeces is not a problem: the anal sacs still somehow empty effectively. However in some individuals, the sacs fill up with secretion, and when they become swollen, they start to be itchy. This is why dogs start to scoot along the ground. Sometimes the scooting behaviour solves the problem: some dogs are able to naturally empty their own anal sacs by doing this. But in most cases, the anal sacs remain over-full and itchy, and human intervention is needed to sort things out.

Emptying Anal Sacs

Emptying over-full anal sacs is a simple procedure that owners should be able to learn to do themselves. It’s best to have a few lessons from your vet first, but once the technique has been learned, it can be a useful skill.

Squeezing the anal sac is probably the most unpleasant part of a vet’s job.

  • Latex gloves are essential.
  • The area around the anus is squeezed firmly, and the accumulation of anal sac fluid is physically emptied onto a piece of cotton wool.
  • The latex glove is then discarded into a sealed clinical waste bin.
  • The smell of anal sac secretions is strong, musky, and disgusting, similar to the stench of a skunk.
  • There are occasional incidents where the secretion squirts in the wrong direction, escaping confinement within the latex glove. If this happens, it can leave a foul smell on your hands, or on your clothing, which is exceptionally difficult to remove. 
black and brown dog lying down

Veterinary Intervention

Occasionally, simply squeezing out the anal sacs is not enough, and the problem continues. At this stage, veterinary intervention is definitely needed. Anal sacs can become infected and may need to be flushed out, or in rare cases, surgical removal may be needed. 

Anal Gland Abscess

In other cases, when the area under the tail is examined, it’s obvious that there’s more going on than simply over-full anal sacs. The area to one side of the anus can become red and swollen, and there may even be a hole in the skin, exuding a bloody discharge. This is a problem known as an “anal gland abscess”. In these cases, an infected anal gland has filled with pus and ruptured. It’s a painful problem that can be difficult to treat, requiring high levels of antibiotics and frequent bathing of the affected area. Again, a visit to the vet is essential so that the correct treatment can be given before the problem becomes too advanced.

Fortunately, most “scooting” dogs never suffer from this serious type of complication. In most cases, the anal sacs only need to be emptied once. To prevent future recurrences of over-full anal glands, vets often suggest that extra fibre should be added to the diet e.g. a teaspoonful of bran every day, sprinkled onto the dog’s dinner. 


  • “Sledging” or “scooting” is often a sign of anal sac problems.
  • Affected animals usually need to have their anal sacs squeezed out.
  • Additional fibre in the diet can prevent recurrence of anal sac problems.