A metallic taste is usually nothing serious. Upper respiratory infections, such as a cold or a sinus infection, can change your sense of taste. In this case, the problem will clear up when your sickness does. Do you notice it whenever you eat something specific (such as shellfish or nuts)? If so, it could be a sign of a food allergy, and you should bring it up with your primary care doctor or an allergist. Another possibility: pregnancy. Many women notice changes to their sense of taste when they’re expecting. Multivitamins containing heavy metals (copper or zinc, perhaps) and certain cold remedies (like zinc lozenges) may also cause a metallic taste. Some Rxs can create an odd taste in the mouth, too, including certain antibiotics, as well as some blood pressure, glaucoma, and osteoporosis meds.