It is one of the commonest symptom women present to a doctor.
It is quite normal for a woman to have vaginal discharge. Normal vaginal discharge is usually clear, white or slightly yellow which is non foul smelling or irritating. The amount of discharge generally varies during the cycle itself.
The vagina, just like the skin and bowel, has lots of friendly bugs (bacteria) that help us everyday of our lives. If the environment in the vagina changes (e.g. sex, change in diet, long periods sitting down, pregnancy, menopause, taking hormones) the friendly yeast or bacteria can overgrow and become a nuisance. If a discharge becomes foul smelling, discoloured or irritating it is usually simply an overgrowth of the friendly yeast or bacteria that normally live in the vagina in very small amounts. So while the discharge naturally causes concern, it is usually nothing to worry about unless it is persistent, associated with changes on PAP (cervical cancer screening) test or mixed with blood.