Cat Anal Sacs
Cats have two anal sacs under the tail on each side of the anus. The sacs have glands that produce a thin liquid made from apocrine glands (sweat) and sebaceous oil glands. A narrow duct connects the sac to the external surface on the anus.
The anal sac liquid has a pungent odor with a mixture of various bacteria and fungi. They are similar to skunk scent glands, however cats are not able to shoot the anal sac material in the direction of the feared animal.
The sacs are located under the skin on each side of the anus.
Under healthy conditions, the glands will empty with bowel movements or when the cat is frightened. When alarmed the sacs are expressed by the muscles around it. The pungent odor leaves a scent marking territory and a warning to other animals something bad happened here that was scary. That is one reason some animals are afraid at the veterinary facility.
In a safe home environment, cats rarely empty the anal sacs. They are not suddenly terrified. If the ducts are not cleaned daily with self grooming, the liquid can start to dehydrate causing a plug in the duct.
Older, obese or arthritic cats cannot get under the tail to clean the area with daily tongue grooming. The dried anal sac material forms a dark plug at the duct of the anal sac easily viewed when the tail is elevated.
The sac can be palpated from the outside. A full anal sac is approximately 1 cm in diameter, at that point they need expressing.
A gloved hand can carefully express the sacs to relieve the pressure. Some full anal sacs will rupture causing an abscess of the skin. Topical treatments and possible antibiotics are needed to heal the wound.
Impacted anal sacs can lead to pain and a variety of associated issues. The cat may be less active, hiding, dehydrated, lame, and have selective appetite.
Addressing the underlying issue of obesity, pain, with lack of grooming the area can prevent another episode of impacted anal sacs.
Have a look under the tail, if black dots are seen on each side of the anus, covering the duct openings, the area can be gently lubricated, moistened, and the duct cleaned of the pasted debris.
Consult your veterinarian for learning how to express the sacs. Most anal sac expressions can be done awake if performed gently. Some cats require a skilled tech hold to express the sacs of the dehydrated material which is often a dark paste consistency.


















