A bad taste in the mouth can be a result of a wide range of medical conditions and even everyday situations. Many different kinds of prescription or over-the-counter medications can interfere with the sense of taste and may produce an unpleasant sensation of taste. The feeling of a bad taste in the mouth is usually temporary and improves when the underlying cause is remedied. Consumption of certain foods, or the use of tobacco products, can result in an unpleasant or bad taste in the mouth. Poor dental health and poor hygiene are other potential causes of a bad taste in the mouth.
Dysgeusia is the medical term for an impaired sense of taste. It can result in unpleasant taste sensations ranging from metallic to salty or bitter. The bad taste may also be described as foul or rancid. The severity of the bad taste varies among affected individuals. Dysgeusia can be caused by infections, inflammation, injury, or environmental factors. A history of radiation therapy to the head and neck can also cause a bad taste in the mouth. Sometimes, women in the early stages of pregnancy find that their sense of taste appears to have changed, possibly resulting in a bad taste in the mouth.