Most owners first hear about anal glands when the smell hits — that sharp, fishy odor during cuddle time or after their dog scoots across the rug. It is easy to assume this is routine maintenance, like nail trims. In day-to-day practice, I counsel the opposite: healthy anal sacs are self-emptying, and routine squeezing can irritate tissue that was doing fine on its own.
Two small sacs sit at roughly 4 and 8 o’clock around the anus, lined with sebaceous and apocrine glands that produce a pungent, oily secretion. That fluid is scent signature, not waste. During a normal bowel movement, firm stool presses against the sacs as it passes and flattens them enough to release a small amount. That is why stool quality matters more than most grooming checklists suggest. A dog passing consistently firm stools may help maintain normal emptying without any hands-on help, while chronic soft stool removes that natural pressure.
What those little sacs do and why firm stool matters
It helps to think of the sacs as collapsible pouches with a tiny duct to the skin surface. Muscle around the anus contracts, stool provides counter-pressure, and a droplet marks the stool. Diarrhea, low-fiber diets, obesity, allergies, poor muscle tone, and anatomy — small breeds and bulldog-type conformations seem overrepresented — can interrupt that cycle. Fluid thickens, ducts narrow, and impaction develops.
This is where I am honest where the preventive evidence is thin. Fiber and weight management support normal gastrointestinal function and may help maintain regular anal sac emptying, but no supplement or pumpkin scoop has been shown to prevent impaction in every dog. What supports prevention in real life is simpler: consistent, well-formed stools, healthy weight, and prompt attention to itching or soft stool rather than a calendar schedule for expression.
A four-year-old, 22-pound French Bulldog mix came in after three weeks of intermittent scooting and licking after walks. Her owner had watched online videos and wondered if she should buy gloves and learn external expression to save vet visits. On the table the dog was bright, stools at home were mostly soft despite a recent food change, and both sacs were full but soft and non-painful. We talked through why her case was about stool form and skin allergies, not a grooming gap, and made a plan to firm stools and recheck in 10 days rather than start monthly squeezing. By day 10 the scooting had stopped without any expression at all.
Signs that point to impaction, infection, or abscess
Leave normal dogs alone. Intervene for signs.
Call your veterinarian promptly for scooting more than a day or two, persistent licking or biting at the rear, chasing the tail, yelping when sitting or defecating, a fishy odor that lingers, swelling beside the anus, redness, discharge, blood, or a hot, painful lump that could signal an abscess. According to VCA Hospitals, impacted sacs can progress to sacculitis and abscessation, and abscesses may rupture through the skin and need flushing, pain control, and antibiotics.
Do not try to push through pain, thick or bloody discharge, green-yellow pus, fever, or a dog that will not let you near the tail. Those point past simple fullness. The Merck Veterinary Manual describes the same spectrum from impaction to infection to abscess and tumor, which is why recurrent one-sided swelling, non-healing sores, or firm nodules deserve an exam rather than another squeeze.
Why I do not teach routine at-home expression for most families
External expression looks simple on video and that is the problem.
Proper technique still risks bruising, tearing the delicate duct, pushing infected material deeper, or missing a mass. Internal expression, with a gloved finger inside the rectum, is more complete but carries more risk for pain, injury, and infection if done without training and restraint. Fear matters too. A dog that learns the rear is a place where it gets pinned and squeezed becomes harder to examine next time, which delays diagnosis when something serious appears.
A seven-year-old, 68-pound Labrador Retriever taught me this tradeoff the hard way. His owner, trying to help, had attempted external expression every two weeks for two months after watching a groomer do it. Each time very little fluid came out, but the scooting worsened. By the time we saw him the left sac was thickened and tender, the secretion was gritty and blood-tinged, and he yelped on palpation. We stopped home attempts, treated sacculitis, adjusted fiber, and addressed his weight. He needed fewer interventions afterward, not more.
If your vet or groomer has specifically asked you to maintain a dog with chronic, non-infected fullness between visits, ask for hands-on coaching first, with gloves, lubricant, good lighting, and a Fear Free setup. Most owners I see do better splitting grooming this way, as described in At-Home Grooming vs a Professional Groomer: How to Split the Job. Stop and call if nothing comes easily, the dog shows pain, or the fluid looks abnormal.
What a professional check actually includes
A trained exam checks both sides for size, symmetry, thickness, pain, and character of the fluid, plus surrounding skin, perineal hernias in older intact males, and lumps that could mimic impaction. That context is lost with a quick squeeze at home.
How to lower the odds your dog needs expression at all
Focus upstream.
Feed a consistent, complete diet that yields firm, pick-up-able stools and address soft stool early rather than waiting it out. Keep weight lean — extra perianal fat changes mechanics. Manage itch: food or environmental allergies often show up as rear licking long before ears flare. Keep grooming irritation low with gentle bathing habits outlined in How Often Should You Bathe Your Dog? A Vet’s Guide by Coat and Skin Type and avoid harsh wipes or fragrances around the rear.
Exercise that supports muscle tone and regular bowel habits helps. So does watching output. Individual dogs vary widely, and what is normal frequency for one Beagle is not a rule for your Shih Tzu.
A nine-year-old, 14-pound Shih Tzu mix showed the edge case owners miss. She had never scooted, but her owner noticed a pea-sized, non-painful swelling on the right that did not change across three weeks. No odor, no licking, normal 14-pound stools. Because it was one-sided, persistent, and firm, we did not express at home and instead aspirated in clinic to rule out a mass rather than assuming impaction. It was inspissated material, but that pause for diagnosis was the right call — recurrent or asymmetric swelling should always be examined first.
Where I land on doing it yourself
My recommendation is narrow on purpose.
Do not express healthy anal glands at home on a schedule. Monitor, support firm stools and healthy skin, and let your vet or experienced groomer check sacs when there are signs or as part of a visit for a dog with known issues. Say yes to learning only if your vet has diagnosed recurrent simple fullness, shown you the technique on your specific dog, and set clear stop rules.
That restraint protects tissue, preserves trust, and keeps the warning signs visible.
Frequently asked questions
How do I know if my dog's anal glands are full?
You cannot tell by looking. Scooting, rear licking, fishy odor, straining, or swelling beside the anus suggest a problem, but only a vet exam can distinguish simple fullness from infection, abscess, or a mass.
How often do dogs need their anal glands expressed?
Most dogs never need it. Dogs with diagnosed recurrent impaction may need periodic checks, while pain, swelling, discharge, or one-sided lumps should be examined promptly rather than expressed at home.
Sources
- Anal Sac Disease in Dogs — VCA Hospitals