It is usually abnormal.
Normally, the vagina can have a slight odour that changes with the menstrual cycle, but if the vagina develops an unpleasant abnormal odour such as a fishy or foul smell, it is mostly due to an infection of the reproductive tract and needs prompt treatment if the symptoms persist for a long time and are accompanied by itching, burning or a change in the colour or other properties of the vaginal discharge.