What Are Anal Glands and What Do They Do?
Anal glands, also called anal sacs, are two small glands located just inside your dog's anus, one on each side, at approximately the four o'clock and eight o'clock positions. Each gland produces a small amount of oily, foul-smelling fluid that is unique to every individual dog. This secretion is deposited onto faeces as they pass through, which is why dogs are so interested in sniffing one another's rear ends — it is a sophisticated form of chemical communication that conveys identity, sex, health status, and territory information.
Under normal circumstances, the pressure created during defecation is sufficient to empty the glands naturally. The majority of dogs go through their entire lives without ever needing manual assistance with their anal glands.
Signs of Anal Gland Problems
Although most dogs empty their anal glands naturally, some do develop problems. The most commonly reported signs include:
- Scooting — dragging the bottom along the floor or carpet. While this is frequently associated with anal gland discomfort, it can also be caused by intestinal worms, skin irritation, or allergies, so it is not a definitive indicator on its own.
- Persistent licking or biting at the area around the tail base or anus.
- A noticeable fishy or foul smell coming from the rear end, even outside of defecation.
- Visible swelling or redness on one or both sides of the anus.
- Reluctance to sit, or suddenly sitting and then getting straight back up again.
- Straining or appearing uncomfortable when trying to defecate.
- Vocalising when touched near the tail base.
Why Most Dogs Never Need Manual Expression
It is a widespread myth that all dogs need their anal glands expressed regularly. Veterinary guidance is clear on this: if a dog is defecating normally and showing no signs of discomfort, the anal glands should be left alone. Routine manual expression in dogs with healthy, functioning glands is unnecessary and may actually be counterproductive. Repeated unnecessary expression can irritate the delicate tissue of the sac lining, and some research suggests it may over time reduce the gland's ability to empty on its own.
Natural emptying relies on the right combination of muscle tone around the anal sphincter, faecal consistency, and adequate fibre in the diet. When all of these factors are working together, the glands do their job without any help.
Who Should Express Anal Glands
When a dog does need their anal glands expressed, this should be carried out by a vet or an experienced professional groomer. Home expression by untrained owners is not recommended for most people and carries real risks if done incorrectly.
Professional groomers typically perform external anal gland expression, which involves applying gentle pressure on the outside of the gland through the skin. This is appropriate for glands that are full but otherwise healthy.
Internal expression, where a gloved finger is inserted into the rectum to apply pressure directly to the gland, should only be performed by a vet or vet nurse. This technique is required when the glands are impacted — meaning the secretion has become thickened and cannot be expressed externally — or when there is an infection, abscess, or other complication. It is a clinical procedure and not something owners should attempt at home.
Risks of Unnecessary Home Expression
Attempting to express your dog's anal glands at home without professional guidance or a specific instruction from your vet carries several risks:
- Inflammation of the gland and surrounding tissue, particularly if done too frequently or with excessive force.
- Introduction of bacteria, increasing the risk of infection or abscess formation.
- Impaction, where rough handling causes the secretion to become compacted rather than released.
- Pain and distress to the dog, which can make future examinations and veterinary visits more difficult.
- Masking an underlying condition that actually requires veterinary diagnosis and treatment.
If your vet has specifically instructed you to perform home expression as part of an ongoing management plan for your individual dog, they will demonstrate the correct external technique. In that context only, you can apply gentle outward pressure to the glands through the skin using a tissue or cloth. If you are unsure whether you are doing it correctly, or if your dog shows signs of pain, stop and contact your vet.
Diet and Fibre's Role in Anal Gland Health
Diet plays a significant role in anal gland health. Dogs who eat a diet that produces well-formed, firm stools are far less likely to have anal gland problems than dogs who frequently pass loose or soft stools. Firm stools apply more consistent pressure to the glands during defecation, which aids natural emptying.
Adding fibre to the diet can help dogs who repeatedly have anal gland issues. Options include adding a small amount of plain tinned pumpkin (not pie filling), cooked sweet potato, or a veterinary-recommended fibre supplement to your dog's food. Your vet can advise on the appropriate amount for your dog's size and current diet. Some dogs benefit from a prescription diet designed to produce firmer stools.
Maintaining a healthy body weight is also important, as overweight dogs tend to have reduced muscle tone around the anal sphincter, which can impair natural gland emptying.
When a Vet Visit Is Urgent
Some anal gland conditions require prompt veterinary attention. Do not delay if you notice any of the following:
- Visible swelling, a lump, or a soft, painful area on either side of the anus — this may indicate an abscess.
- Discharge of blood or pus from the area around the anus.
- An open sore or wound near the anus, which can indicate a ruptured abscess.
- Your dog is in obvious pain, crying out, or refusing to let you near the area.
- Anal gland problems keep recurring every few weeks despite professional expression.
Impacted anal glands that are not treated can become infected. An infected gland can progress to an abscess, which is extremely painful and may rupture through the skin, requiring antibiotics, pain relief, flushing, and sometimes surgical intervention. Recurring problems may indicate an underlying allergy, dietary intolerance, or anatomical issue that warrants further investigation.
If your dog is showing any of the warning signs described in this article, the right first step is always a consultation with your vet. They can examine the glands properly, express them safely if needed, and advise on the most appropriate long-term management plan for your individual dog.