you know what? i dont know, all i know is that the first time i had a uti i was so ashamed/embarassed to tell anyone*ignorance* and i didnt know how to take care of it..i thought if i used antibacterial soap it would work...and 1 day later the itching stopped, a few days later all of my symptoms ceased. and i have been washing with antibacterial soap ever since..and have not experienced any problems.