What Causes White Vaginal Discharge?

Hi, may I answer your health queries right now ? Please type your query here...i am 23 year old girl and have problem of white discharge, i had already consulted to my dr she said its normal and gave me shampoo "lactaacyd" but still i m facing the same problem even more than from before medicine..i am very tensed why it is happening is anything serious what i need to do??