A metallic taste in your mouth is a type of taste disorder known medically as parageusia. This unpleasant taste can develop suddenly or over longer periods of time. To understand what causes a metallic taste you must first understand how taste works.
Your sense of taste is controlled by your taste buds and your olfactory sensory neurons. Olfactory sensory neurons are responsible for your sense of smell. Your nerve endings transfer information from your taste buds and olfactory sensory neurons to your brain, which then identifies specific tastes. Many things can affect this complex system and, in turn, cause a metallic taste in the mouth.
There are many possible causes for a metallic taste in your mouth.
Distorted taste is a common side effect of certain medications. These medications include:
- antibiotics, such as clarithromycin (Biaxin) or metronidazole (Flagyl)
- blood pressure medications, such as captopril (Capoten)
- glaucoma medications, such as methazolamide (Neptazane)
- osteoporosis medications
Chemotherapy and Radiation
According to the American Cancer Society, certain types of chemotherapy and radiation can cause a metallic taste. This side effect is sometimes called “chemo mouth.” Studies suggest that certain vitamin supplements, such as vitamin D or zinc, can help prevent taste distortion in people undergoing radiation therapy or chemotherapy. This suggests that certain vitamin deficiencies may be a contributor to taste distortion.
Your sense of taste is closely related to your sense of smell. When your sense of smell is distorted, it can have an impact on your sense of taste. Sinus issues are a common cause of metallic taste in the mouth. Sinus issues can be caused by:
Central Nervous System (CNS) Disorders
Your CNS sends messages to the rest of your body, including messages about taste. A CNS disorder or injury, such as stroke or Bell’s palsy, can distort these messages. This can result in impaired or distorted taste.
Some pregnant women report a metallic taste, especially early in their pregnancy. The cause is unknown, but some believe it’s caused by the change in hormones experienced during early pregnancy. Others have attributed an increase in the sense of smell, a symptom commonly associated with pregnancy, as the cause.
Metallic taste has been identified as a symptom of some food allergies. If you experience distorted taste after eating a type of food, such as shellfish or tree nuts, you may have a food allergy. Speak with your doctor if you believe you have a food allergy.
Middle Ear Surgery
Middle ear and ear tube surgery is often performed due to chronic ear infections, or otitis media. Occasionally, chorda tympani, a structure close to the inner ear that controls taste in the rear two-thirds of the tongue, may be damaged during surgery. This can result in distorted taste or parageusia. One case study showed significant improvement in taste with medication management.
A metallic taste in your mouth will often go away once the underlying cause has been treated, especially if the cause is temporary. You should contact your doctor if the bad taste persists. Your doctor will often refer you to an otolaryngologist, also known as an ear, nose, and throat doctor. An otolaryngologist may order a taste test to help determine the cause and extent of the taste disorder. Taste tests measure a person’s response to different chemicals. Your doctor may also order imaging studies to look at your sinuses.
Loss of taste can be a serious issue. Taste is important for identifying spoiled foods. Taste also helps you feel satiated after a meal. Distorted taste can lead to malnutrition, weight loss, weight gain, or depression. For people who must stick to certain diets, such as those with diabetes, distorted taste can make it challenging to eat the required foods. It can also be a warning sign of some diseases, including Parkinson’s or Alzheimer’s diseases.
Unfortunately, there is often little you can do to prevent a metallic taste in your mouth. If sinus issues are to blame, the taste distortion should go away once the sinus issue resolves itself. If the taste distortion is caused by a medication, speak to your doctor about alternative options.
Finding ways to mask the metallic taste may help while you wait for it to go away, especially if it is caused by chemotherapy, pregnancy, or other long-term treatments or conditions. Here are some ways you may reduce or temporarily eliminate taste distortion:
- chew sugar-free gum or mints
- brush your teeth after meals
- experiment with different foods, spices, and seasonings
- use nonmetallic dishes, utensils, and cookware
- stay hydrated
- avoid smoking cigarettes
There are also medications that may improve taste after development of parosmia (smell distortion) or ear surgery. Speak with your doctor to learn more about your options.