On and off for two weeks i have had a metallic smell and taste in my mouth and nose. i was taking a multivitamin and mineral and also magnesium. ?

Metallic taste.: Could possibly be an issue of reflux, acid coming up from the stomach creating this taste. Do you have any new medications? Had recent dental work done?

Many causes: Could be the supplements you are taking. Could also be change in other medications or OTCs, bleeding (infected) gums, abscessed teeth, post-nasal drip, diet change, circadian rhythm change, allergy, etc. see both your Denist and your Physician.