The phenomenon referred as a "sour taste in mouth" is an elusive entity about which a lot can be said, but very little that is conclusive. To sum it up, theories and sufferers propose that it can be causes by foods (obviously), periodontal disease, underlying disease, vitamin deficiencies, neurological disorders, drugs, dry mouth, and even pregnancy. If you have a persistent problem try to work your way through it by considering your own particular circumstances. Food and pregnancy are easy to rule out - if either of these could be the cause, it will probably pass.

Are you taking any drugs regularly? Many drugs have mild to severe side effects including sour taste in mouth. If possible, discontinue the drug or replace it with another alternative and wait to see if the taste problem clears up. if you can't discontinue or change the drug, you may have to resort to using an oral rinse or mouthwash on a regular basis to keep the problem at a manageable level. If you suspect that the drug is causing dry mouth or gum disease, you may be able to resolve the taste problem by treating the underlying one.

Do you have any underlying disease that might cause a sour taste in mouth? If you have stomach problems, sinus problems, diabetes, respiratory problems, or any one of a host of other medical conditions, you may have found the explanation. Consult your doctor to try to determine if this is the cause. If you don't have any such conditions, telling your doctor about your sour taste in mouth may help him or her to diagnose a previously unrecognized condition.

A neurological disorder is another possibility. Because the brain interprets smells and tastes based on information sent from our sensory organs, a damaged, stressed or diseased brain can misinterpret and tell us that things smell bad when they really are not offensive, or create a phantom sour taste in mouth that really is not there. Recall that epileptic seizures are often preceded by sensory illusions of smell and vision. Though this is probably an uncommon cause of a persistent unpleasant taste, it's worth considering and checking out if the taste recurs or remains constant.

Periodontal disease frequently generates a offensive taste in the mouth, although describing it as a sour taste in mouth is unusual. If periodontal disease is associated with dry mouth - and it often is because a lack of saliva can increase the risk of gum disease and tooth decay - taste may be affected simply because there is not enough saliva to keep the taste buds healthy and moist. Again, treat the dry mouth and the bad taste may very well go away.