Pregnancy
Pregnant women may get the metallic taste in the early stages of their gestation as a result of hormonal changes. Iron deficiency has also been shown to trigger smell and taste disturbances which may cause the metallic taste.
Kidney failure
If the taste is accompanied by excessive urination, little urination, bloody stools, decreased appetite, flank pain, no urine, high blood pressure, seizures or body swelling, you probably have a kidney problem and should see your doctor as soon as you can.
Diabetes
Diabetes doesn’t have obvious symptoms and may be hard to detect using just a metallic taste in your mouth. However, it is important that your dentist checks you and refers you to a specialist, if necessary, to rule out this chronic condition.
Metformin, a common diabetes medication, is also likely to cause a metallic taste in your mouth.
Neurological diseases
Alzheimer’s, dementia and other neurological problems can also cause taste disturbances and, eventually, a metallic taste in your mouth as the brain struggles to interpret signals from the taste buds. Strokes, tumors, brain lesions, Parkinson’s disease, and Bell’s palsy are among the other neurological disorders that can cause taste disturbances.