What Anal Sacs Are and the Signs of Trouble
Every dog has two small anal sacs (often called anal glands) tucked just under the skin on either side of the anus, positioned roughly at the four o'clock and eight o'clock points. Each sac stores a pungent, oily fluid produced by glands in its lining, and that fluid is the dog equivalent of a scent signature, carrying information about identity, sex, and status that other dogs read during the familiar rear-end greeting. Under normal conditions the sacs empty themselves: as a firm stool passes and presses against the rectal wall, it squeezes the sacs and a small amount of fluid is released along with the bowel movement. This is why the system is designed to be hands-off in a healthy dog. Trouble begins when that natural emptying fails and the fluid is retained, thickens, and the sacs cannot drain on their own.
The earliest and most recognizable sign of anal sac disease is scooting, where a dog drags its rear along the floor or grass trying to relieve pressure and itch. Close behind are excessive licking or biting under the tail and around the anus, a reluctance to sit, straining during defecation, and a distinctive fishy or metallic odor that owners often notice before they understand its source. From there the condition tends to follow a predictable arc. First comes impaction, when retained secretions thicken and the sacs feel firm and full. If retained fluid becomes a home for bacteria, impaction can turn into sacculitis, an infection marked by pain and inflammation. Untreated infection can progress to an abscess, a swollen, intensely painful pocket of pus, which may eventually rupture through the overlying skin and drain. Recognizing the signs early, while a dog is merely scooting and licking, is far better than meeting this problem at the abscess stage.
Why Anal Gland Problems Happen
The single most important idea is that anal sacs depend on firm, bulky stool to empty, so anything that softens or shrinks the stool removes the gentle internal pressure that keeps the sacs clear. Chronically soft stool, diarrhea, or persistently small stools simply do not exert enough force during defecation to compress the sacs, so fluid accumulates and stagnates. This is one reason episodes of digestive upset, low-fiber diets, and food sensitivities so often run alongside anal gland flare-ups. Skin and allergic disease play a role too: dogs with food allergies, atopic dermatitis, or seborrhea can develop inflammation around the sac openings that narrows the ducts and interferes with drainage, which is why anal sac problems and itchy skin frequently appear in the same patient.
Obesity is one of the leading modifiable risk factors, and the reason is mechanical. Excess fat in the perianal region changes the position and angle of the sacs and blunts the muscle tone and pressure that normally squeezes them during a bowel movement, so an overweight dog's sacs simply do not empty well. Anatomy and breed matter as well. Anal sac disease is far more common in small and toy breeds, with Chihuahuas, and toy and miniature Poodles among the classically predisposed, while large and giant breeds are affected much less often. Most cases appear in adult dogs rather than young puppies. In practice these factors stack: a small, overweight dog with intermittently soft stool and itchy skin has several of the major risk factors working against it at once.
When to See a Veterinarian
Mild, early scooting and licking warrant a call to your veterinarian for an evaluation, but certain signs mean the problem has advanced and should not wait. Visible swelling beside the anus, redness or a hot, painful lump, blood or pus in the discharge, a foul draining sore, or a dog that is lethargic, off its food, or yelping when it sits all point toward infection, an abscess, or a rupture. An abscess that has burst leaves an open, draining wound that needs prompt professional care to clean, drain, and treat with appropriate medication, and a veterinarian can determine whether antibiotics, pain relief, sedation, or even surgery is required. Because tumors of the anal sac can occasionally mimic ordinary impaction, any persistent firm mass in the area also deserves a hands-on veterinary exam rather than guesswork at home.
There is an important nuance that often gets lost in grooming culture: expression is a treatment for symptomatic dogs, not a routine maintenance step for healthy ones. If a dog's sacs empty normally on their own and the dog shows no scooting, licking, odor, or discomfort, there is no need to have the glands squeezed at every grooming appointment. Manipulating normal, healthy sacs unnecessarily can irritate the delicate tissue and ducts, and may even contribute to the inflammation it is meant to prevent. The right move is to let a veterinarian confirm whether a dog genuinely needs its glands expressed, and how often, rather than treating expression as a default service. When a dog truly is symptomatic, however, a professional should evaluate it promptly so impaction is caught before it escalates to infection or abscess.
The Diet Angle: Fiber and Weight
Because the sacs are designed to empty under the pressure of a firm, bulky stool, dietary fiber is the most direct nutritional lever an owner has. Adequate fiber adds water-holding bulk and structure to the stool, producing a larger, firmer bowel movement that presses more effectively against the sacs and helps them release their contents the way nature intended. This is precisely why a higher-fiber diet is the standard long-term recommendation for dogs that suffer repeated anal gland problems, and why chronically loose or wispy stools tend to perpetuate the cycle of impaction. Improving stool quality is not a quick cosmetic fix; it addresses the underlying reason the sacs are not emptying. Any sustained change to fiber intake, whether through a different complete diet or a veterinarian-approved addition such as plain pumpkin or a fiber supplement, should be made gradually and ideally with professional guidance so the dog's digestion adjusts smoothly.
The second nutritional lever is weight, and it works hand in hand with fiber. Since excess perianal fat physically shifts the sacs and weakens the natural pressure that empties them, helping an overweight dog reach a lean, healthy body condition can meaningfully reduce the frequency of flare-ups. For dogs carrying extra pounds, a calorie-controlled, satisfying weight-management dog food can support steady fat loss while keeping the dog full, and many such formulas are also higher in fiber, which means a single dietary change can address both levers at once. The goal is not a crash diet but a sustainable trajectory toward an ideal weight, monitored by a veterinarian who can confirm the pace is safe. Pairing firmer, bulkier stools with a leaner body restores the mechanics the anal sacs rely on, making them far more likely to empty on their own.
Doing Expression Right and the Bottom Line
When a dog genuinely needs help emptying its sacs, expression should be done correctly and only as often as that individual dog requires. A veterinarian or trained groomer can manually express the sacs, and a veterinarian can flush them or infuse medication when the contents are thick, dry, or infected. Some owners learn to express at home for a chronically affected dog, but this is best taught hands-on by a professional, because clumsy or overly frequent squeezing can bruise the tissue and worsen irritation. Between treatments, keeping the area clean, managing any underlying allergies or skin disease, and maintaining good stool quality all reduce the odds of a relapse. Expression relieves the immediate impaction, but it does not fix the reason the sacs filled up, so it works best alongside the dietary and weight strategies that target the root cause.
The bottom line is that anal gland problems are common, uncomfortable, and largely manageable once you understand the mechanics. Watch for the telltale trio of scooting, licking under the tail, and a fishy odor, and act early before impaction has a chance to progress to infection, abscess, or rupture. Lean on the two diet levers that address the underlying cause: enough fiber to produce firm, bulky stool that empties the sacs naturally, and weight management to remove the excess fat that knocks the sacs out of position. Reserve manual expression for dogs that actually need it rather than making it a default at every groom, and let a veterinarian guide diagnosis, the expression schedule, and any signs of abscess or rupture. With the right diet and a healthy weight, many dogs return to emptying their sacs on their own, exactly as the system is meant to work.
Frequently asked questions
What food helps dogs express anal glands naturally?
No single food is magic, but the key is a diet that produces a firm, bulky stool, because that is what naturally presses on the anal sacs and empties them during a bowel movement. Diets with adequate fiber tend to do this best, and a veterinarian may suggest a higher-fiber food or a vet-approved addition such as plain pumpkin. For overweight dogs, a leaner body also helps the sacs empty properly, so weight and fiber work together.
Why does my dog keep having anal gland problems?
Recurring problems usually mean the underlying cause has not been addressed. Chronically soft or small stools fail to press on the sacs, so they do not empty, and excess body weight shifts the sacs and weakens that pressure. Allergies, skin disease, and being a predisposed small breed such as a Chihuahua or toy Poodle also drive repeat flare-ups. Expression treats the symptom, but lasting relief usually comes from firmer stool, a healthy weight, and managing skin issues with your veterinarian.
Is a dog anal gland abscess an emergency?
An anal gland abscess is a serious problem that needs prompt veterinary care, even if it is not always a middle-of-the-night emergency. Signs include a painful, swollen lump beside the anus, redness, and discomfort sitting, sometimes with blood or pus. If the abscess ruptures it leaves an open, draining sore that must be cleaned and treated. Contact your veterinarian right away, especially if your dog is lethargic, refusing food, or in obvious pain, because delay lets the infection worsen.
For diet-side context, see Weight-Management Dog Food, Best Dog Food for Sensitive Stomachs. To check whether your dog’s food matches the rubric criteria discussed above, paste the ingredient list into the KibbleIQ analyzer. For scoring methodology context, see our published methodology.
Related condition deep-dives: Obesity in Dogs · Diarrhea in Dogs.