It's one of the least glamorous moments of dog ownership: your dog plants its rear on the carpet and drags itself across the room, often with a proud expression that suggests it has just solved a problem you didn't know existed. That scoot is easy to laugh off, but it's usually a message. More often than not, it's your dog telling you that its anal sacs — two small scent glands tucked just inside the anus — are full, irritated, or infected. Anal sac disease is common, uncomfortable, and, left alone, can turn into something genuinely painful. Here's what those little glands actually do, how to read the warning signs, and when a scoot is a nuisance versus an emergency.
What the Anal Glands Actually Do
Your dog has two small sacs positioned at roughly the four-o'clock and eight-o'clock positions around the anus. Each is lined with glands that produce a distinctively pungent, oily fluid — the source of that unmistakable "fishy" smell. In a healthy dog, these sacs empty naturally each time a firm stool passes and presses against them, depositing a tiny scent marker. This is why dogs are so interested in each other's rear ends: the anal sac secretion is essentially a chemical ID card, carrying information about the individual dog.
The system works beautifully when stools are firm and the ducts stay open. Problems begin when the fluid doesn't get expressed on schedule. It thickens, the sacs swell, and what should be a routine bit of scent-marking becomes a source of pressure and pain.
How Common Is It, Really?
More common than most owners realize. A large VetCompass study from the Royal Veterinary College, which reviewed the records of more than 100,000 UK dogs, found that roughly 4.4% of dogs were diagnosed with an anal sac disorder in a single year. Of those cases, the overwhelming majority — about 79% — were simple impaction, where the sacs fill and can't empty. Around 12% had progressed to sacculitis (inflammation and infection), and nearly 9% had developed a painful abscess. In other words, the problem usually starts mild and escalates only if it goes unaddressed.
The Warning Signs
Scooting is the signature symptom, but it's rarely the only one. Watch for a cluster of behaviors that all point to rear-end discomfort:
- Scooting or dragging the rear along the floor, especially repeatedly over several days.
- Excessive licking or biting at the anal area or the base of the tail.
- A strong fishy odor — full sacs leak, and the smell is hard to miss.
- Straining or discomfort when passing stool, or looking back at the rear repeatedly.
- Redness, swelling, or a pimple-like bump beside the anus — a sign the problem has advanced to infection or an abscess.
An occasional scoot after a bowel movement isn't cause for alarm. But if your dog scoots after most bowel movements over the course of several days, or you notice licking paired with that fishy smell, the sacs likely need attention.
From Full to Infected: How It Escalates
Anal sac disease is really a spectrum. It begins with impaction — the sacs fill with thickened secretion and can't empty on their own. This is uncomfortable but manageable, and expressing the sacs usually brings quick relief. If impaction persists, bacteria multiply in the trapped fluid and the sac becomes inflamed and infected — sacculitis. Left untreated, that infection can build into an abscess: a swollen, painful pocket of pus that may eventually rupture through the skin, leaving an open, bleeding wound near the anus.
An abscess is where a minor annoyance becomes a real problem. It's painful, it requires veterinary treatment — often lancing and draining the sac, followed by antibiotics and pain relief — and it can recur. The takeaway is simple: dealing with a full gland early is far easier, cheaper, and kinder than dealing with an abscess later.
Which Dogs Are Most at Risk
Any dog can develop anal sac problems, but some are far more prone. The VetCompass data showed the highest rates in Cavalier King Charles Spaniels (nearly 15%), King Charles Spaniels, Cockapoos, Bichon Frises, and Shih Tzus. Flat-faced (brachycephalic) breeds like the Shih Tzu carried roughly 2.6 times the risk of longer-nosed breeds such as Border Collies. Small breeds in general appear more susceptible than large ones.
Beyond breed, the biggest everyday risk factor is soft stool. Firm, bulky feces are what naturally press the sacs empty; chronically loose stools from food sensitivities, low-fiber diets, or gut issues rob the sacs of that natural squeeze. Obesity is another contributor — extra fat around the rear changes the anatomy and makes natural expression less effective, which is one more reason to keep your dog at a healthy weight.
What You Can Do at Home
The single most effective preventive measure is unglamorous but powerful: firmer stools through more dietary fiber. Because the sacs rely on the pressure of a bulky stool to empty, adding fiber often solves recurrent problems at the source. Veterinarians commonly suggest plain canned pumpkin (not pie filling), a fiber supplement, or a switch to a higher-fiber diet, sometimes alongside fish oil. Always confirm the amount with your vet, since needs vary by size and health.
Keeping your dog lean, well-hydrated, and active also helps the whole system work as designed. You may have seen advice to express the glands yourself at home. It can be done, but for most owners it's best left to a vet or groomer — done incorrectly or too frequently, manual expression can irritate the ducts and actually make recurrent problems worse. Routinely squeezing healthy glands that are emptying fine on their own isn't recommended.
When to See the Vet
Call your veterinarian if your dog is scooting persistently, licking the area constantly, or if you notice that fishy smell that won't quit. These signal sacs that need to be professionally expressed and checked. Seek care promptly — same-day if possible — if you see redness, swelling, a bump like a coming-to-a-head pimple beside the anus, bleeding, or signs of real pain such as crying when sitting. Those point to infection or an abscess, which won't resolve on their own and get more painful by the day.
A vet can also look past the glands themselves. Persistent scooting sometimes reflects allergies, parasites like tapeworms, or other skin issues, so a proper exam rules out the look-alikes. If your dog suffers repeated bouts, your vet can help build a long-term plan — diet changes, weight management, regular expressions, or in stubborn cases surgical removal of the sacs.
The Bottom Line
Anal gland trouble is common, usually mild at the start, and very manageable when you catch it early. Learn your dog's normal, treat a scoot as information rather than just a punchline, and lean on fiber and a healthy weight to keep those little sacs doing their job quietly. When the signs tip toward swelling, pain, or that pimple-like bump, don't wait it out — a quick vet visit turns a would-be abscess back into a five-minute fix.