Anal Glands: Which Dogs Have Problems, and Should They Be Expressed?
About 1 in 23 dogs at UK vets has an anal gland problem each year, some breeds far more. What the data show, and why routine emptying has no evidence.
Written by thecanineledger
This page carries no advertising, and nothing on it is for sale.
“Plausible risk factors along with therapeutic and preventative recommendations are frequently described but rarely substantiated in the veterinary literature.” That’s a team at the Royal Veterinary College, writing in Veterinary Record in 2021 about anal gland problems in dogs (O’Neill et al., 2021).
While advice to have a dog’s glands emptied every few weeks is everywhere online, we found no study that tested it. What we did find is the largest study of the problem: over 100,000 UK dogs. It shows who gets anal gland trouble, and how little else is known.
1. What anal glands are
Anal glands, which vets call anal sacs, are two small sacs by a dog’s anus.
Problems run along a scale. The RVC team lists “impaction, inflammation (sacculitis), infection and abscessation”. It says these are usually seen as one process, starting with “a disturbance in the normal emptying process of the anal sacs.”
2. Signs
The paper describes the discomfort as “scooting, rubbing, licking, biting”, along with “discomfort when sitting” and straining.
Scooting isn’t proof of a gland problem. The authors note that if scooting stops after the sacs are emptied, that “can help to discriminate ASD from perianal self-trauma due to other causes”. ASD stands for anal sac disorder. They also warn that itchy skin from allergies can be mistaken for gland trouble: “misattribution of (peri)anal self-trauma to ASD in dogs with allergic perianal pruritus” is possible.
If there’s a painful swelling beside your dog’s anus, or a wound there that is bleeding or leaking, see a vet the same day.
Our note: The same-day advice for a swelling or a burst abscess is ours, not the paper’s. A dog in obvious pain or with a fever needs to be seen promptly.
3. How common it is, and which dogs
The study used the records of 104,212 dogs seen at 110 UK practices in 2013. “the 1-year period prevalence of ASD was 4.40%”. That’s about 1 dog in 23 seen for a gland problem in a year.
Some breeds were affected far more than others:
| Breed | Share with a gland problem in a year |
|---|---|
| Cavalier King Charles spaniel | 14.83% |
| King Charles spaniel | 13.78% |
| All dogs | 4.40% |
| German Shepherd Dog | 1.72% |
| Boxer | 1.53% |
Compared with crossbreds, six breeds had higher odds: “Cavalier King Charles spaniel, King Charles spaniel, Cockapoo, Shih-tzu, Bichon Frise and Cocker spaniel”. Flat-faced types had “2.6 times the odds for ASD compared to dolichocephalic types”, the long-nosed breeds.
The true figure is probably higher. The authors note that owners and groomers may deal with glands without a vet, so some cases never reach the records.
4. What the evidence doesn’t show
Weight. Overweight dogs are often said to be at risk. The study found no link with body weight compared with the breed average, which it says “fails to provide any evidence supporting an association between obesity and ASD.” Body weight is only a rough stand-in for obesity, so this doesn’t settle it.
Fibre. Diet is often recommended. The authors say “the true value of diet for prevention or therapy of ASD remains uncertain.”
Routine emptying. We found no study of emptying the glands in dogs that have no problems. In dogs that do have problems, emptying “may be effective to relieve immediate anal sac impaction”, but “recurrence remains a problem.” In one small study the authors cite, “Repeated expression was necessary every 2 months in one study of 20 dogs with ASD, with signs reappearing within a median of 3 weeks.”
The paper’s conclusion lists what’s still unknown: “aetiopathogenesis, diagnostic criteria, therapy, prevention and risk factors.” In plain terms, almost everything.
Our note: We found no evidence for or against routine emptying in healthy dogs.
5. Treatment
In the study, “12% of dogs” received pain relief and “20% of ASD cases” received antibiotics. Surgery to remove the sacs was done in under 1% of cases.
The authors raise a concern about the antibiotics. They say more work may be needed on good antimicrobial stewardship, because the use isn’t backed by firm evidence. → Does Diarrhoea Need Antibiotics? What the Evidence Says
Our note: The paper cites guidelines that favour treating inside the sac before using antibiotics by mouth. We haven’t read those guidelines.
6. What to ask your vet
- Is this a gland problem, or could it be itchy skin or something else?
- Does my dog’s breed make this more likely?
- If the glands need emptying, how will we know when it’s needed again?
- Is an antibiotic really needed this time?
7. What we could not verify
| Commonly said | What we found |
|---|---|
| “Have the glands emptied every 3–4 weeks” | No study found. Nobody has tested a schedule in healthy dogs. |
| “Scooting means full glands” | Not always. Allergies can cause the same signs. |
| “Overweight dogs get gland problems” | No link found in the largest study. |
| “Extra fibre prevents it” | Uncertain, the authors say. |
Sources
- O’Neill DG, Hendricks A, Phillips JA, Brodbelt DC, Church DB, Loeffler A. Non-neoplastic anal sac disorders in UK dogs: epidemiology and management aspects of a research-neglected syndrome. Veterinary Record 2021 (peer-reviewed cohort study of 104,212 dogs, VetCompass; funded by the Kennel Club Charitable Trust and Agria Pet Insurance, which had no input into the study; open access, full text read 4 November 2026)
Always confirm with your vet before acting on anything on this page.