What can cause metallic taste in mouth for days?

Most often: A side effect of many medications. It is not a serious condition and is quite common. If it persists beyond a few weeks, consult with your physician or dentist. Make sure you are maintaining good oral hygiene.

Metallic taste: Many times this taste is a result of gingival bleeding. If your gums are red, swollen and /or bleeding, this would explain the taste. As was mentioned, medications can aslo alter taste. In other cases, problems with the middle ear can cause a tast alteration often presenting as a metallic taste.