What exactly are a cat's anal glands and what do they do?

Cats have two small anal sacs located at roughly the 4 o'clock and 8 o'clock positions just inside the anus, each lined with glands that produce a thick, foul-smelling brown or yellowish fluid used for scent marking and individual identification between cats (Cornell Feline Health Center, n.d.). Under normal circumstances, the pressure of a firm bowel movement empties a small amount of this fluid along with the stool, so most cats go their entire lives without an owner ever noticing the glands exist. Veterinary literature classifies true anal sac disease as uncommon in cats compared with dogs, which is one reason sudden signs are often mistaken for a behavior problem rather than a medical one (Cornell Feline Health Center, n.d.).

Because the sacs sit just under the skin on either side of the rectal opening, any swelling in that specific area — rather than generalized rectal or perineal swelling — is the first clue pointing to the anal glands as the source. Veterinarians typically confirm gland involvement with a gentle rectal palpation during a physical exam, checking whether the sacs feel firm, distended, or unusually tender compared to a normal soft, easily expressed sac (Merck Veterinary Manual, 2024).

What are the first signs an owner notices when something's wrong?

The most common early sign is scooting — dragging the rear end across the floor — along with excessive licking or biting at the base of the tail and a strong, fishy odor that lingers even after litter box use. Some cats develop a visibly swollen or reddened area just to one side of the anus, and owners occasionally spot a small amount of blood-tinged or pus-like discharge on bedding or fur (ASPCA, n.d.). Cats are also notoriously good at masking pain, so a subtler tell is a change in tail carriage or reluctance to let the tail area be touched or groomed, which many owners initially chalk up to general crankiness.

As impaction progresses toward infection or abscess formation, cats often show more systemic signs: reduced appetite, hiding, restlessness, or difficulty settling into a comfortable sitting position. A firm, painful lump beside the anus that the cat resents having touched is a strong indicator the sac has become distended enough to need professional attention rather than home management (Merck Veterinary Manual, 2024).

Why do some cats get impacted or infected anal glands in the first place?

Anal gland impaction happens when the sac's secretions become too thick to express normally during defecation, causing the material to back up, harden, and distend the gland. Chronic soft stool or diarrhea is a frequently cited contributing factor because loose stool doesn't generate enough pressure against the anal sacs to empty them properly, while obesity can also make it physically harder for a cat to express its own glands during normal movement (Cornell Feline Health Center, n.d.).

Underlying skin allergies, inflammatory bowel disease, or other conditions that alter stool consistency or perianal skin health are sometimes associated with recurrent gland problems, and untreated impaction itself is the main pathway to infection: bacteria proliferate in the stagnant, backed-up secretions, turning a plugged sac into an abscess that can rupture through the skin if not drained (Merck Veterinary Manual, 2024). Anal gland tumors, though rare, are another reason veterinarians recommend having any persistent or recurring swelling checked rather than assuming every case is a simple impaction.

How does a veterinarian actually diagnose the problem?

Diagnosis starts with a hands-on rectal exam in which the veterinarian palpates each sac to assess size, firmness, symmetry, and pain response, since a healthy gland should express fairly easily while an impacted one will feel tight and swollen (Merck Veterinary Manual, 2024). If the sac appears infected or abscessed, the vet will look for warmth, redness, and possible skin discoloration over the swelling, and may take a sample of the expressed material to check under a microscope for bacteria or abnormal cells.

Because recurrent or unusual anal gland swelling can occasionally signal an anal sac tumor — a form of adenocarcinoma reported in cats, though far less common than in dogs — veterinarians may recommend fine-needle aspiration or biopsy of any firm, non-resolving mass rather than assuming it will respond to routine expression alone (Cornell Feline Health Center, n.d.). Bloodwork is sometimes added if a cat is systemically unwell, to rule out other causes of the lethargy or appetite loss.

What treatments do vets use for impacted, infected, or ruptured glands?

Simple impaction is usually treated by manually expressing the glands during the exam, which immediately relieves pressure and pain in most cases; the veterinarian may also flush the sac with saline or an antiseptic solution if the material is especially thick (Merck Veterinary Manual, 2024). If infection is present, a course of oral antibiotics is typically prescribed, along with pain medication, since infected sacs are notably tender and cats often resent further handling of the area during recovery.

A ruptured or abscessed gland requires more intensive care: the wound is usually flushed and left open to drain and heal by secondary intention rather than sutured closed immediately, and cats often go home with an Elizabethan collar to prevent licking or chewing at the site while it heals over one to two weeks (Cornell Feline Health Center, n.d.). Cats with tumors of the anal sac are referred for surgical evaluation, since surgical removal combined with further staging is generally the recommended course when a mass is confirmed to be neoplastic.

Can anal gland problems be managed or prevented at home?

For cats with a history of soft stool contributing to poor gland emptying, veterinarians commonly recommend adding fiber to the diet — either through a therapeutic high-fiber cat food or a fiber supplement such as psyllium — to help firm stool and encourage natural gland expression with each bowel movement (Cornell Feline Health Center, n.d.). Maintaining a healthy body weight also matters, since excess weight can restrict a cat's normal movement and posture during defecation, indirectly reducing how effectively the glands empty on their own.

Owners should never attempt to express a cat's anal glands at home without specific veterinary instruction, since improper technique can bruise the tissue, push material the wrong direction, or mask a developing infection that needs medical treatment rather than manual pressure. Cats prone to recurrent impaction may need scheduled expression appointments every few weeks to months, a routine the veterinary team can tailor based on how quickly the problem tends to recur in that individual cat (Merck Veterinary Manual, 2024).

What's the long-term outlook for a cat with recurring anal gland issues?

Most cats with a single episode of impaction or infection recover fully with expression, antibiotics if needed, and time, and many never have a second episode once any underlying cause like chronic soft stool is addressed. Cats with a pattern of recurrence, however, may need lifelong dietary management and periodic veterinary checks, since repeated infections raise the risk of scarring around the duct opening, which can itself make future blockages more likely (Cornell Feline Health Center, n.d.).

In the rare cases involving an anal sac tumor, prognosis depends heavily on how early it's caught and whether surgery achieves clean margins, underscoring why any anal gland swelling that doesn't resolve with standard treatment, or that recurs in the same spot repeatedly, deserves a more thorough diagnostic workup rather than repeated rounds of expression alone.