There are plenty of reasons you may have a metallic taste that aren't related to pregnancy or your sense of smell. Antibiotics and anti-thyroid and neurological drugs are just a few of the medications that may cause dysgeusia. People undergoing chemotherapy and radiation -- as well as those recovering from surgeries where anesthesia was used -- also may report experiencing a metallic taste both during and after treatment. Those suffering from head and neck cancers and other various medical conditions, like Bell's palsy, Parkinson's disease, diabetes and gastroesophageal reflux disease, may also have a persistent metallic taste as a side effect [source: Danoff].
Unhealthy practices like smoking or having poor dental hygiene can also cause a foul metallic taste. Oral infections such as gingivitis and periodontitis often cause gums to bleed. The iron that is released as blood breaks down in the mouth can leave a strong metal taste behind. To prevent this from happening, combat dental disease and bacteria by scraping your tongue, brushing your teeth twice a day and flossing regularly.
Dysgeusia can also be caused by a vitamin or mineral deficiency, like B-12 or zinc, or an overdose of a particular nutrient, dietary supplement or a food containing potentially toxic ingredients. An overdose of selenium -- a mineral found in seafood, lean red meat and Brazil nuts -- can cause a metallic taste. Excessive zinc consumption could also produce this condition as a side effect [source: Srilakshmi].
Perhaps the most serious cause of a metallic taste is clupeotoxin poisoning. This potentially fatal condition occurs after consuming plankton-eating fish such as sardines, herring, tarpons or bonefish contaminated with the toxin. This poison can not only cause one's mouth to taste like metal, but the victim can become violently ill, and approximately 50 percent of cases of clupeotoxin poisoning result in death. Besides dysgeusia, symptoms can include blue-tinged fingers, toes, nose and lips, vomiting, diarrhea, lightheadedness, abdominal pain and a drop in blood pressure [sources: Hui, WebMD].
Even though most common causes of a metallic taste are easily treated, if the condition is persistent, it's important to see a doctor for a diagnosis. If you'd like to know more about why your sense of taste could become impaired, check out the links on the next page.