The bottom line first: anal glands are not something every dog needs emptied on a schedule. A healthy dog empties them while passing a stool. The dogs that need a hand are the ones showing signs that this is not happening.
Come back from the groomer and you are often told the anal glands were "done." What rarely comes with that is any explanation of what they are or why they would need doing. The anal sacs are two small pouches, one on each side of the anus. VCA Animal Hospitals describes their position, in clock terms, as roughly the four o'clock and eight o'clock positions. In size, think of a pea in a small dog and a grape in a large one.
Inside each pouch is a strongly scented fluid. To a human nose it is simply a fishy smell; to a dog it is closer to a personal scent signature. When a stool is passed, the muscles around the anus contract and a little of that fluid is squeezed onto it, leaving a marker that says "I was here." The way dogs greet each other by sniffing rear ends is tied to the same secretion. Which is to say that the anal sacs are designed to be emptied by defecation itself. In a dog with no problems, the whole process passes without the owner ever noticing it.
Trouble starts when that natural emptying stops working. If stools stay soft, there is not enough pressure around the anus to press the sacs, so they empty incompletely, and whatever stays behind loses water and thickens. The Merck Veterinary Manual describes the contents of an impacted sac as a thick, pasty, brown secretion. Once it reaches that state, passing through a narrow duct becomes harder still, and because it will not pass it thickens further โ a loop that feeds itself.
Which dogs block up? Cornell's Riney Canine Health Center lists the contributing factors as food-allergy dermatitis, atopic dermatitis, anatomic abnormalities, chronic diarrhoea, constipation, obesity and low-fibre diets. Size plays a part too: the same source notes that smaller dogs have problems more often, with Chihuahuas the most commonly affected, while German Shepherds are over-represented among large breeds. It typically shows up after one year of age, with no sex predisposition. The detail worth pausing on is that skin allergy sits on that list. A fair share of dogs whose anal glands keep flaring are really dogs whose allergies are not under control.
The famous sign is scooting โ dragging the rear end along the floor. But scooting does not mean "the anal glands are blocked" so much as "something around the anus is uncomfortable." Anal glands are simply the most common reason for that. So rather than reading scooting on its own, it helps to look at it alongside the rest.
| What you see | What it usually means | What to do |
|---|---|---|
| Dragging the rear end along the floor | Discomfort around the anus. Anal glands are the commonest cause but not the only one | See a vet within days |
| Persistent licking or biting at the tail base or anus | Ongoing irritation; the licking itself breaks the skin down | See a vet within days |
| A sudden fishy smell | Secretion is leaking out | Check the area, then book a visit |
| Reluctant to sit, tail held down, painful when touched | The painful stage | Same-day visit |
| Postures to defecate but strains without result | Avoiding defecation because it hurts | Same-day visit |
| Red, hot swelling beside the anus | Suspected abscess | Same-day emergency visit |
| The swelling bursts, discharging yellow or bloody pus | Ruptured abscess | Go now |
The row owners most often miss is the smell. If your dog was bathed recently and yet the spot where they sit, or the bedding, carries a fishy odour, that is not a cleanliness problem โ it is a fair sign that anal sac fluid is leaking. The other easily missed one is the lowered tail. It is easy to read that as low mood or wariness, but a dog whose anal area hurts will hold the tail down to keep anything from touching it. If sitting looks awkward, or your dog sits with one hip lifted, consider pain.
Conversely, a single rub of the rear end followed by running about perfectly happily is not a run-to-the-clinic moment. Watch that one over a few days, judging by whether the frequency climbs and whether licking starts too. All of this, though, is a framework for observation only โ the actual diagnosis has to come from a veterinarian. The area around the anus is one where very different things can look much the same from the outside.
This is the part of the article that has to be written honestly. Whether anal glands should be expressed on a routine schedule is genuinely disputed.
On one side sits long-standing practice. In Korean grooming salons and self-service bath shops, expressing the anal glands is a default part of the bath, and the advice given is that this is what prevents problems. Owners of small dogs that block up easily often do get through years this way without incident.
On the other side sits the as-needed view. Sources in this camp argue that a healthy dog's sacs empty through defecation and so need no handling, and that expressing more often than necessary can cause irritation and inflammation, or leave the dog dependent on manual emptying and less able to do it naturally. Several US veterinary clinics use exactly that language and summarise it as finding the middle ground between neglect and over-handling. Cornell likewise attaches a condition, suggesting periodic palpation and expression for dogs with recurrent problems.
To be fair, though, the claim that routine expression genuinely degrades function is clinical impression rather than something confirmed by large studies. The opposite claim โ that every dog should be done regularly โ is equally short of evidence. The practical compromise runs like this. If your dog has never scooted or licked at the area, rather than fixing an interval, ask the groomer simply to check the area and respond when a sign appears. If your dog blocks up every few weeks, that is the dog worth setting a personal schedule for with the vet. The thing to avoid is applying one interval to every dog.
Anal sac disease generally progresses in one direction. Being able to guess which stage you are at makes the decision about when to go in far easier.
| Stage | What is happening inside | What you see | Usual treatment |
|---|---|---|---|
| Normal | Emptied by muscle contraction during defecation | No signs at all | Nothing needed |
| Impaction | Secretion thickens to a paste and blocks the duct | Scooting, licking, fishy smell | Expression, saline to soften if needed |
| Sacculitis | Bacteria multiply; the fluid becomes blood-tinged | Pain, swelling, reluctance to sit | Flushing, antibiotic-steroid infusion, oral antibiotics |
| Abscess | The duct stays blocked while pus builds | Red, hot swelling beside the anus | Sedation, lancing and draining, antibiotics, pain relief, warm compresses |
| Rupture | The skin gives way under pressure | An opening beside the anus, yellow or bloody pus | Wound care, a cone, several weeks of healing |
Treatment shifts with the stage. For inflamed sacs, the Merck Veterinary Manual describes repeated weekly flushing combined with infusion of a steroid-antimicrobial ointment into the sac, and notes that for pain relief hot compresses applied every 8โ12 hours for 15โ20 minutes are beneficial. Before copying that at home, the thing to establish is whether this is still a stage where compresses are appropriate. If the sac already needs lancing, repeating warm compresses only loses time.
The moment owners most often regret is waiting until it burst. Abscesses frequently swell over a day or two, so "he was completely fine yesterday" is not the reassurance it sounds like. If there is a bulge beside the anus with heat in it, get seen that day. If it has already ruptured and is draining, it is better to stop your dog licking at it and head straight in than to start applying antiseptic at home. Human disinfectants and ointments applied on your own initiative make the wound harder to assess.
If the sacs have been emptied and the scooting carries on, the cause may lie elsewhere. Plenty of things make the area around the anus uncomfortable.
The one owners most often overlook is the irritation left behind by diarrhoea. Even once stools have firmed up again, the skin around the anus heals more slowly than the gut does. If you want to work out why the stools went soft in the first place, dog diarrhoea and what the colour tells you lays that out. Dogs with recurring diarrhoea are also dogs whose anal sacs empty poorly, so the two problems tend to arrive together.
A dog that has blocked once tends to block again, which makes what comes after treatment more important than the treatment itself. Management comes down to two things: keeping stools firm enough that defecation presses the sacs by itself, and getting the weight down.
Weight first. Fat around the anus weakens the pressure the surrounding muscle can put on the sacs, and muscle tone drops as well, with a background tendency to inflammation on top. That is why obesity appears on so many lists of risk factors. If you want to check whether the amount you are feeding is right, our dog food portion calculator will give you a daily baseline. Counting treats into that total often reveals more food than expected.
Dietary fibre bulks out the stool and creates the pressure that empties the sacs during defecation. The US magazine Whole Dog Journal puts typical adult maintenance fibre at 2.5โ5% on a dry matter basis, and suggests 5% or higher may help dogs with existing anal gland problems. It is worth knowing that these are recommended figures rather than thresholds established by large studies. When adding fibre, cooked pumpkin or sweet potato worked into the daily treat calorie allowance is a reasonable approach; increasing it sharply tends to backfire by loosening the stool. Raise it over several days and watch what the stools do.
Water follows the same logic. Too little and stools turn hard, and an over-hard stool makes defecation difficult in its own way. Our dog water intake calculator gives you a baseline so that "drinking less than usual" becomes a number you can quote. Finally, if your dog has allergies, managing those is managing the anal glands โ bring the itching under control and the gland flare-ups often ease with it. And simply making a habit of looking at the area at bath time, and glancing at the stools, will catch the next episode far earlier.
There is no single interval that fits every dog, and this is exactly where sources disagree most. In Korea, emptying the anal glands is a long-standing part of the standard grooming bath, and many salons advise that this is what keeps problems away. On the other side, clinics that favour an as-needed approach argue that a healthy dog with no symptoms empties the sacs during defecation and has no reason to be handled at all, and that expressing too often can cause irritation and inflammation or leave the dog dependent on manual emptying rather than doing it naturally. That concern, to be fair, comes from clinical experience rather than from large studies, and there is no solid trial evidence that routine expression genuinely damages function. Cornell's material lands in the middle, suggesting periodic palpation and expression for dogs with recurrent problems, on a schedule set by their own vet. So if your dog has never scooted or licked at the area, rather than fixing an interval, ask the groomer simply to check the area and act when a sign appears. If instead your dog blocks up every few weeks, that is the dog worth setting an individual schedule for with your vet. The point is not to apply the same interval to every dog.
Generally no. Veterinary sources advise attempting it only after a vet has shown you how and you feel genuinely confident. There are two reasons. First, the method most owners use at home is the external technique, squeezing from outside the anus, and that tends to move only the surface secretion while leaving the thickened material deeper in. Whatever stays behind keeps blocking the duct, and the same symptoms return within days. Clinics generally use the internal technique, with a gloved finger inside the rectum so the sac can be emptied between finger and thumb, which empties it far more completely. Second, if the sac is already inflamed and painful, pressure hurts a great deal, and a thinned sac wall can be damaged or pushed closer to rupturing. If nothing comes out after a couple of attempts, or your dog reacts painfully, stop there and go to the clinic. If what came out contained blood or pus, this is already past simple impaction and needs to be seen.
Yes โ anal sacculectomy, considered when repeated impaction and abscesses cannot be controlled by management, or when there is a tumour. There is a reason it is kept as a last resort. The sacs sit right beside the nerves and muscles that control defecation, so faecal incontinence is the complication most often cited. VCA notes that some dogs have loose stools or difficulty controlling bowel movements for one to three weeks after surgery, and that in rare cases this becomes chronic. The Merck Veterinary Manual notes that among the surgical techniques, the closed excision method has the lowest complication rate. So if surgery is proposed, it is fair to ask why it is needed now, which technique will be used, and how much experience the clinic has with it. The reassuring side is that most anal sac disease never reaches surgery at all: Cornell describes the prognosis for non-cancerous anal sac disease as good.
That is one to have examined rather than watched. Older dogs can develop tumours in the anal sac, and in its early stages anal sac adenocarcinoma is almost indistinguishable from simple impaction or infection. According to Cornell, this tumour makes up about 2% of skin tumours in dogs, the average age at diagnosis is around ten years, and there is no sex predilection. A good number of cases are found incidentally on a rectal examination done for some other reason. The signs worth noticing are lethargy, straining to defecate or new constipation, reduced appetite, drinking and urinating noticeably more, and swelling or weakness in the hind limbs. The change in thirst matters because this tumour can raise blood calcium. The same source reports metastasis to the sublumbar lymph nodes in about 50% of dogs and to the lungs in 2โ13%, notes a better outlook for tumours under 2.5cm, and states that some dogs have an average survival of more than three years. In other words, finding it early changes the outcome substantially. If only one side feels firm, or the area is swollen but nothing comes out when expressed, make a point of telling the clinic that.
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Written and reviewed by the Mongnyang Lab editor ยท Last updated 2 August 2026
This article was compiled by cross-checking publicly available veterinary and pet nutrition sources. Where sources disagree, that disagreement is stated rather than smoothed over. The Mongnyang Lab editor is not a veterinarian, and this article does not replace diagnosis or prescription. If your animal seems different from usual, going to a clinic is always better than reading further.
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This content is general information and does not replace veterinary diagnosis. If the area around the anus is swollen or painful, contact a veterinary clinic immediately.