College of Veterinary Medicine > Veterinary Teaching Hospital > Animal Health > Anal sac disease

Anal sac disease

Image by Simon Kadula on Pixabay.
Image by Simon Kadula on Pixabay.

When your dog scoots its rear end across the floor it most likely isn’t due to worms. Dogs scoot when their anal sacs are uncomfortable. Anal glands and anal sacs are part of normal canine anatomy, and every canid from wolves to Chihuahuas have them.

What are anal glands and anal sacs?

Anal glands are scent glands located around a dog’s anus that produce a strong-smelling, oily secretion that is stored in the animal’s anal sacs, located between the internal and external anal sphincters (the muscles that allow the dog to keep stool in the rectum until it is time to pass). The secretion is stored for territory marking. The anal sacs empty through two openings located on either side of the dog’s anus. When the anus is stretched as stool is passed, the sphincter muscles squeeze the anal sacs and force the contents onto the surface of the stool. 

When dogs greet each other with familiar sniffing, the secretion from the anal glands is what they are smelling. Anal sacs vary in size based on the breed of the dog, but generally healthy anal sacs range in size from a pea to a kidney bean. 

What happens if a dog’s anal sacs become impacted?

If the contents of the anal sacs are not emptied on a regular basis during the act of passing stool, the normally liquid contents become very thick and plug the openings of the anal sacs. The impacted glands can cause discomfort or can get infected and result in an abscess. Fluid from a normal anal sac does not have a pleasant smell, but if infected the smell can be overwhelmingly bad. 

Should my dog have its anal glands checked?

To ensure the anal sacs are emptying properly, have them checked on a regular basis. This is a simple and painless procedure that should be included in a complete physical exam. If the glands are full, they can be easily emptied while the contents are still fluid. It becomes more difficult to empty the anal sacs when the contents begin to thicken. 

What are some signs my dog is having issues with its anal glands?

If you are unsure if your dog needs its anal sacs emptied, watch his or her behavior. Dogs with impacted anal glands will often scoot their rump, or they may look, lick, and/or bite at their anus.

What should I do if my dog is having issues with its anal glands?

If your dog is having issues with its anal glands, schedule an appointment with your veterinarian or at the WSU Veterinary Teaching Hospital by calling 509-335-0711.

This information is not meant to be a substitute for veterinary care. Always follow the instructions provided by your veterinarian. Washington State University assumes no liability for injury to you or your pet incurred by following these descriptions or procedures.