Canine anal glands, also called anal sacs, seem to be a topic of conversation at the groomer and vet's office. Those outside of the veterinary community, however, generally avoid this icky part of the canine anatomy. Though unpleasant, your dog's anal glands perform several important functions.
Every canine has two small anal glands, roughly the size of a black bean, located inside his anus on either side. They sit between the internal and external anal sphincter muscles. Though hidden from the outside, your veterinarian can easily feel the left and right anal glands during a rectal exam.
Sometimes referred to as scent glands, anal glands secrete a dark, oily liquid used to delineate territory, scent mark and even as self-defense to ward off predators. Most dogs release a drop or two of the fishy-smelling material each time they defecate, when the stool compresses the sphincter muscles and subsequent anal glands. Dogs suffering from chronic loose stools, gastrointestinal upset, allergies or anal sac disease are often unable to empty their anal glands on their own, and may need them professionally expressed. Consult your veterinarian if your dog shows any signs of anal gland discomfort such as scooting, licking the anus and chasing his tail or if you notice any redness or swelling in the area.