Metallic Taste in Mouth: Causes and Treatment Oral B UK A metallic taste in your mouth can be a sign of conditions ranging from gingivitis and pregnancy to dementia and kidney failure. What to know: Vitamin B12 is essential for healthy oral tissues. Its deficiency can affect the mouth early.., Oral effects , red,smooth,painful tongue(glossitis), recurrent mouth ulcers , burning mouth 5 Reasons You Get a Metallic Taste in Your Mouth (And How to Avoid It) What causes a metallic taste in the mouth?