Why Do Dogs Have Anal Glands?

dog sniffing butt
Anal glands in dogs may actually diffuse pheromones to communicate with other dogs. borisz/Getty Images

OK, your dog's anal glands are not a pleasant topic for anyone. So, we are going to get in, get some useful information, and get out as quickly as we can. And this is some really gross anatomy we're talking about so you're probably gonna want to put down that sandwich.

Anal glands are two sacs about the size of small grapes on both sides of your dog's anus, just under their tail. Genuine apologies if that ruins grapes for you. These sacs are filled with an oily substance that smells kind of fishy, or kind of skunky, depending on who is doing the sniffing. Presumably to dogs, it smells terrific.


Science hasn't pinned down exactly why dogs have these glands at all, but they do seem to serve a few purposes. They likely lubricate the pooping process and disperse their scent for marking purposes. It's also possible that the glands diffuse pheromones to communicate with other dogs (hence the reason they sniff each other's butts).

When Good Glands Go Bad

When everything is going great, you don't have to think about the structure of your dog's anus at all. Congratulations. But if you notice your dog doing any of the following, particularly if it's a small breed, you might have some anal gland problems to deal with:

  • Scooting their bum across the floor
  • Licking their rear-end area, a lot
  • A noticeable (and horrible) odor
  • Swelling and redness in the area

If things get very bad back there, your pup may even have an abscess that needs to be drained. (We really hope you put down that sandwich when we warned you back in the first paragraph.)


There are a couple of common ways for the anal glands to get stopped up, like food allergies and local infections. Both diarrhea and constipation can cause problems because in both situations, there's not enough pressure from feces passing through the anus to squeeze the fluid out properly.

Whew. Take a break here if you need to. Think of flowers, like big, pretty, nice-smelling roses. After a fresh rain. So fresh.


Treating and Preventing Stinky Glands

We're rounding third and headed home! Things get less gross from here on. If you see the symptoms mentioned above, it's worth taking your dog to the vet to be checked and maybe have the anal glands expressed. Basically that means the vet will squeeze the glands and manually empty them. You do not want to do this yourself. Seriously. Not only is it pretty dang disgusting, but your vet can also see what might be causing the problem in the first place and help you prevent future flareups in your dog.

If your dog has an infection or inflammation, your vet may prescribe medicine like antibiotics or steroids to help clear things up. If the problem is serious and recurring, your dog may even need to have their anal glands surgically removed.


There are a few simple things you can do to help keep this whole situation from flaring up in the first place:

  • Make sure your dog is eating a healthy diet and getting lots of exercise.
  • Increase your dog's fiber intake for bulkier poos that do more, um, squeezing action.
  • Give your dog plenty of fresh water to drink to keep things moving.