The term FLUTD (feline lower urinary tract disease) describes a collection of conditions that can affect the bladder and/or urethra of cats.

Signs of FLUTD include increased frequency of urination, straining while urinating, crying out while urinating, blood in the urine, urinating outside the litter box, increased grooming of "private parts", or altered behavior (hiding/fear/aggression). Recurrence of clinical signs is usually self-limiting, typically lasting 4-7 days.

The majority (55-69%) of cases are idiopathic (no known causes). Recent research suggests FIC (feline idiopathic cystitis) may result, in part, from alterations in the protective layer that lines the bladder, which normally functions to prevent bacteria and crystals from sticking to the bladder lining. When the protective lining becomes damaged, noxious substances within the urine can get into the bladder wall and cause inflammation, discomfort, and blood to appear in the urine.

Adding glucosamine to a cat's diet can reduce the severity or recurrence rate of clinical signs in cats with recurrent FIC. Feeding more canned food has also been reported to help affected cats.

Stress and anxiety in some cats has been shown to trigger a FIC episode. An antidepressant such as amitriptylline or PROZAC™ may be prescribed, if stress or anxiety is the suspected cause.