Some odors in the vagina are normal and nothing to worry or be concerned about.
However if you have a terrible, really foul smelling odor in your vagina then it could be a cause for concern.
Some things that can cause odor in the vagina are Trichomoniasis, STD's and Urinary Tract Infections or other bacteria.
If your vagina has a really bad fishy smell to it then you likely have a Urinary Tract Infection and should see a doctor.
Most Urinary Tract Infections do go away on their own but it's still good to get a urine sample take and analyzed to see if anything else is going on.
Another cause for vagina odors are yeast infections and other bacterial infections in the vagina.
Subtle vagina smells are nothing to be concerned about but if you notice a severe change in the odor of your vagina you should see a doctor.