Cystitis, or an infection of the urinary tract, in not uncommon in adult female dogs and cats.  These infections are characterized by frequent attempts to urinate, passage of small amounts of urine, urinary discomfort, urination in inappropriate places, and possibly blood or pus in the urine.  They are usually caused by small crystal formation in urine with or without a viral and/or  bacterial infection.  Treatment most commonly includes adjusting diet, high water intake, and possible antibiotic suspension.