Have you ever noticed your dog scooting across the carpet on his bottom? Or a strong, fishy smell coming from your furry friend? There can be several reasons, but anal sac problems are high on the list: anal sac disease is the most common disorder of the anal region in dogs, and scooting is one of its most frequent signs.
The good news is that in most dogs the glands empty on their own every time they poop, so they never need help. When they stop emptying, it is a job for your veterinarian, who can empty them, check for infection and work out why it happened.
What are anal glands?
The anal glands, more correctly called anal sacs, are two small pouches just inside your dog's anus, one on each side at roughly the four o'clock and eight o'clock positions.
The sacs fill with a strong-smelling liquid, and a normal, firm stool squeezes a little of it out as it passes. Its exact purpose is not fully known, but it most likely works as a scent marker that other dogs read when they sniff each other.
Problems start when the sacs stop emptying. The liquid builds up and thickens (impaction), the sac can become inflamed or infected (sacculitis), and an infected sac can turn into an abscess. Our guide to disorders of the anal sac in dogs covers each of these in more depth.
Signs your dog's anal glands need attention
Scooting
Dragging the bottom along the ground is often the first sign, on the lawn, the sidewalk or, inevitably, the living room carpet.
Licking or chewing at the rear
Excessive licking or biting is common too. Many dogs focus on the base of the tail rather than the anus itself, so don't rule out the glands just because your dog is chewing a little higher up.
A strong, fishy smell
Owners often describe a characteristic fishy odor, and you may see traces of discharge where your dog has been sitting or lying. Nervous dogs sometimes leak a little of the fluid when they are frightened.
Straining or not wanting to poop
When the sacs are swollen and sore, passing stool hurts. Your dog may strain, seem reluctant to go, or hold it in, which can lead to constipation and even more pressure on the sore area.
Tail held down and a sore hind end
Some dogs clamp the tail down or act sensitive around the hind end. A painful anal sac can make even a normally gentle dog growl or snap when the area is touched.
Scooting and licking are not always about the glands. Skin allergies and other problems around the anus can cause the same behavior, so let your veterinarian take a look rather than assume.
When to call your vet right away
Book a visit the same day if you notice any of these:
- A red, hot, painful swelling beside the anus
- Blood or pus coming from a small opening in the skin next to the anus (a burst abscess)
- Obvious pain, crying or snapping when the area is touched
- Repeated straining with little or no stool
- Blood in the stool, or a lump you can see or feel near the anus
What your vet does
Your veterinarian will look at the area and do a gentle rectal exam, feeling each sac with a gloved finger to tell whether it is full, impacted, infected, or firm in a way that needs further checks. If the area is very sore, your dog may need sedation so the exam and treatment don't hurt.
Treatment depends on what the vet finds:
- Full or impacted sacs are emptied (expressed), and flushed if the contents are too thick.
- Infected or inflamed sacs are usually flushed, and your veterinarian may place medicine directly into the sac. They choose any antibiotic, anti-inflammatory or pain relief your dog needs, and the dose.
- An abscess is opened and drained, then treated with medicine your vet selects. A cone (Elizabethan collar) may be used to stop licking while it heals.
So do the glands need emptying regularly? Healthy glands that empty normally need no expressing at all. Some dogs with ongoing problems benefit from clinic checks from time to time, but whether that is needed, and how often, is your veterinarian's call.
Which dogs are prone to anal gland problems?
Any dog can develop anal sac problems, but these dogs run a higher risk:
- Small breeds. Among larger dogs, German Shepherds turn up more often than you might expect.
- Overweight dogs, whose poorer muscle tone around the anus means the sacs empty less well.
- Dogs with allergic skin disease, such as food allergy or atopic dermatitis. In one study of 190 dogs with anal sac inflammation, the allergic dogs were more likely to have it come back. See our article on allergic dermatitis in dogs.
- Dogs with chronic diarrhea or constipation. Soft stool doesn't press on the sacs enough to empty them. Our dog poop color chart shows what normal stool looks like.
- Dogs born with anatomic abnormalities of the sacs or ducts.
- Dogs on a low-fiber diet.
Loose stool is one cause among several. Inflammation of the ducts, for example, is a common reason the sacs stop draining. For dogs with repeat problems, your veterinarian may recommend weight loss or more fiber in the diet to make stools bulkier, so ask before changing the food.
Anal sac tumors
Most anal sac problems are impaction or infection, but tumors happen too. The most common is apocrine gland adenocarcinoma of the anal sac: uncommon but potentially serious, usually seen in older dogs (average age around ten), and more frequent in Spaniel breeds.
These tumors are often painless, so they can grow quietly. Signs include swelling near the anus, straining, constipation or blood in the stool, and ACVS notes that in about a quarter of cases the tumor raises blood calcium, which can show up as increased thirst and urination. Many are found when a veterinarian feels a firm, enlarged sac that won't empty during a rectal exam.
That's why the anal sacs are part of a routine checkup, and why a painless lump near the anus still needs a vet visit. Read more about cancer in dogs.
Can the anal glands be removed?
Yes, but it is rarely needed. Surgery to remove the sacs (anal sacculectomy) is considered when medical treatment hasn't worked or when a tumor is present. In a large UK study of first-opinion practices, fewer than 1% of dogs with non-cancerous anal sac problems had their sacs removed.
Anesthesia carries its usual risk, and the surgery is delicate because the sacs sit close to the nerves and muscle that control the anus. The main complication is fecal incontinence, usually temporary but in rare cases permanent. That's why surgery is saved for dogs whose problems keep coming back despite treatment.
Summary
Scooting, licking at the rear or tail base, a fishy smell, straining or a sore hind end mean your dog's anal glands need attention, and swelling, pus, blood or obvious pain mean a same-day vet visit. Leave the emptying to your veterinarian, who can also find the cause and rule out infection or tumors. Keeping an eye on your dog's rear end may feel odd, but it keeps your dog comfortable.
Originally written by Dr. Catharina Hjorth. Updated by the I Love Veterinary editorial team.
Sources
- Merck Veterinary Manual: Anal Sac Disease in Dogs and Cats
- Merck Veterinary Manual (pet owner version): Disorders of the Rectum and Anus in Dogs
- Cornell University College of Veterinary Medicine, Riney Canine Health Center: Anal sac diseases
- American College of Veterinary Surgeons: Anal Sac Tumors in Dogs
- VCA Animal Hospitals: Anal Sac Disease in Dogs
- O'Neill DG et al. Non-neoplastic anal sac disorders in UK dogs: epidemiology and management aspects. Vet Rec 2021
- Hvitman-Graflund K et al. Treatment, outcome, recurrence and concurrent diseases in 190 dogs with anal sacculitis. Vet Dermatol 2023
This article is for general information and is not a substitute for advice from your veterinarian.
