The anal sacs are located on each side of the anus, just under the skin. They open to the outside by tiny passageways or ducts. Glands within the anal sacs produce a dark, foul-smelling substance. The sacs normally empty as the animal has a bowel movement. Their purpose is unknown and your pet can do well without them.

Diseases of the anal sacs fall into three categories:

1. Impaction: The anal sac fluid is abnormally thick and cannot escape.

2. Infection: Bacteria produce a yellow or bloody pus. Infection may also exist in other areas, such as

the eyes, ears, tonsils, and/or skin.

3. Abscessation: As a result of infection, a hot, tender swelling near the anus may rupture and discharge pus and blood.

Signs of anal sac disease include \"scooting\"(dragging the anus on the floor), excessive licking under the tail, tenderness near the tail or anus, and/or bloody or sticky drainage from the anal area.