Cystitis is an inflammation of the bladder due to infection with a microorganism (such as a bacteria or virus). Cystitis is second only to respiratory infections in frequency.

The National Kidney Foundation estimates that 10 to 20 percent of women have had at least one episode of cystitis, and 80 percent of this group has had it recurrently.

Although some cases of cystitis are due to fungus or a virus, most are caused by one of several types of bacteria. The most common, Escherichia coli,...