Medications such as some antibiotics, prenatal vitamins and antidepressants, as well as drugs used to treat high blood pressure, rheumatoid arthritis and kidney stones
Oral problems, including oral infections such as gingivitis or periodontitis, tooth infections, and poor oral hygiene
Sometimes the cause of a metallic taste can't be determined. In many cases, the problem goes away on its own after several months or longer. Proper oral hygiene can help, including regularly brushing your teeth and brushing and scraping your tongue. Done properly, dental restorations — such as fillings and inlays — are rarely the cause a metallic taste."
"the most common causes of a metallic taste are:
Medications such as some antibiotics, prenatal vitamins and antidepressants, as well as drugs used to treat high blood pressure, rheumatoid arthritis and kidney stones
Oral problems, including oral infections such as gingivitis or periodontitis, tooth infections, and poor oral hygiene
Sometimes the cause of a metallic taste can't be determined. In many cases, the problem goes away on its own after several months or longer. Proper oral hygiene can help, including regularly brushing your teeth and brushing and scraping your tongue. Done properly, dental restorations — such as fillings and inlays — are rarely the cause a metallic taste."
http://en.allexperts.com/q/Medical-Research-Internet-1426/copper-taste-mouth.htm