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Anal Sacs

What are they?

Anal sacs are 2 cavities about 5mm long situated either side of the anus at the 4 o’clock & 8 o’clock positions. The lining of the gland is made of secretory cells & each sac has a duct which leads to a small opening just inside the anus.


What is their function?

A pungent secretion normally accumulates in the sacs. This is used in the wild to mark territory, although in domestic animals they have little or no use. The sacs are normally emptied during defaecation but they are often emptied when the animal is frightened.


Problems that may occur

The 2 main problems that may occur are impaction (blockage) & infection. Neoplasia (cancer) of the sacs is possible but quite rare. These problems are often painful & may cause the animal to “scoot” it’s rear along the ground and/or to lick & chew around the area.


  • occurs if normal emptying process fails e.g. due to diarrhoea or abnormal structure
  • uncomplicated cases can be resolved by manual emptying of the sacs by applying pressure from the outside or from within the rectum
  • in some cases emptying may have to be done on a regular basis
  • addition of bran to the diet may help – ask your vet for advice



  • often presents in the same way as impaction but may progress so that an abscess forms in the sac
  • can be sudden in onset
  • very painful due to inflammation
  • bathing the area with warm water may encourage the abscess to burst but emptying is usually necessary
  • antibiotics & anti-inflammatory drugs are usually prescribed, & in a few cases a general anaesthetic is required to flush the glands & introduce antibiotic directly into affected sac(s)


Surgical removal

This may be necessary in recurrent/problematic cases of anal sac disease. It requires the animal to have a general anaesthetic to remove the sacs via 2 small incisions either side of the anus. Animals may be uncomfortable for a few days following surgery, but it does provide relief from the problem quickly.

Recovery is usually complete in 10 days when stitches are removed (as long as the dog is prevented from licking/rubbing the area). Some dogs experience faecal incontinence for a few days & in rare cases this may be a long term problem.