Anal glands are two small sacs sitting just inside the anus, at roughly four and eight o’clock. They produce a strong-smelling fluid that is normally expressed a little at a time when a dog passes a firm stool.
The fluid is a scent marker — part of the individual signature dogs read when they sniff each other. Which is why it smells the way it does.
What goes wrong
Impaction. The fluid thickens and cannot pass. The sacs fill, become uncomfortable, and the dog tries to relieve the pressure.
Infection. Bacteria multiply in retained fluid. The area becomes painful, hot and swollen.
Abscess and rupture. An untreated infection can form an abscess that bursts through the skin beside the anus, leaving an open wound. It is painful and needs veterinary treatment.
Tumours. Uncommon, but anal sac adenocarcinoma exists and is one reason a persistent one-sided swelling should be examined rather than repeatedly expressed.
The signs
- Scooting — dragging the bottom along the floor
- Licking or biting at the anus or base of the tail
- A sudden strong fishy smell, sometimes with a damp patch where the dog has been sitting
- Straining or discomfort when passing a stool
- Swelling or redness beside the anus
- Chasing the tail, or snapping at the back end
- Reluctance to sit, or sitting down abruptly and jumping up again
Scooting does not always mean anal glands
This is worth knowing, because a dog repeatedly expressed for a problem they do not have gets no relief and some irritation.
Other causes of scooting:
- Worms, particularly tapeworm segments around the anus
- Itchy skin from allergies, which commonly affects the perineum
- Faecal matting in long-coated dogs
- Irritation from grooming products or a recent clip
- Fleas
- Rectal or perianal problems, including tumours and fistulas
- Occasionally, simple discomfort after diarrhoea
If your dog scoots and their glands are found to be empty, the answer is elsewhere.
Why diet matters
The sacs empty through pressure from a firm, bulky stool passing by. A dog on a diet that produces persistently soft stool never generates that pressure, which is why chronic soft stool and recurrent anal gland problems travel together.
Practical steps:
- Increase dietary fibre. Plain tinned pumpkin, psyllium husk, or a food formulated with higher fibre. Ask your vet for an amount appropriate to your dog’s size
- Address the cause of soft stool. Food intolerance, parasites, or too many treats and scraps
- Keep your dog lean. Obesity is strongly associated with anal gland problems — fat deposits change the anatomy around the sacs and reduce the pressure that empties them
- Exercise, which keeps gut motility and muscle tone reasonable
For many dogs, fixing stool consistency ends the problem entirely, and it is a more durable solution than regular expression.
Should the glands be emptied routinely?
This is genuinely debated, and the current veterinary consensus leans towards no for dogs with no symptoms.
The arguments against routine expression:
- Repeated manual emptying may cause inflammation and scarring, which can make natural emptying harder over time
- It can create dependence — glands that are always emptied for the dog may stop emptying on their own
- It is uncomfortable
- It can mask an underlying cause, such as allergy or dietary problems, that should be addressed instead
Many groomers offer it as standard. It is reasonable to decline it unless your dog has a diagnosed problem.
Empty them when there are symptoms, and preferably let a vet or nurse do it — internal expression is more complete and more controlled than the external squeeze most groomers perform.
Should you do it yourself?
Most owners should not. It is unpleasant, it is easy to do badly, and done wrongly it causes pain and can worsen inflammation.
If your dog needs frequent expression, that itself is the thing to investigate rather than a routine to learn.
Treatment when things go wrong
Impaction: manual expression, sometimes with an anti-inflammatory.
Infection: expression and flushing, antibiotics, pain relief. Sometimes the sac is infused with medication directly.
Abscess: may need lancing, flushing and a course of antibiotics, occasionally under sedation.
Recurrent problems: investigation of the underlying cause — allergy work-up, dietary trial, weight management. In a small number of dogs with severe, unresolvable recurrent disease, surgical removal of the sacs is considered. It is effective but carries a risk of faecal incontinence, so it is genuinely a last resort.
When to go the same day
- Visible swelling or a lump beside the anus
- Bleeding or discharge
- An open wound near the anus
- Obvious pain, or a dog who will not let you near the area
- A dog who is straining and unable to pass a stool
- Any firm mass that does not resolve after expression
Which dogs are affected most
Small breeds are over-represented — Chihuahuas, Toy Poodles, Cocker Spaniels, Shih Tzus, Dachshunds — though any dog can have problems.
Overweight dogs, dogs with allergies, and dogs with chronically soft stool are the higher-risk groups regardless of breed, and two of those three are things you can change.
