A bitter taste in the mouth can have a wide variety causes, such as vomiting, acid reflux, pregnancy, long-term smoking and injuries to the mouth, nose and head, according to HealthGrades. Even eating certain foods, such as pine nuts, can cause a lasting bitter taste in the mouth, according to the Daily Mail.
A bitter taste in the mouth can be a side effect of chemotherapy as well as a wide range of medications, according to WebMD. These medications include certain types of antihistamines, antibiotics, antifungals and antipshychotics as well as medications used to treat asthma, high blood pressure, high cholesterol, inflammation, diabetes, glaucoma, Parkinson's, gout, anemia, arthritis and seizures.
Dysgeusia, which is a bitter or otherwise foul taste in the mouth, can be a sign of infections of the mouth, according to HealthGrades. It is important to find the cause of the bitter taste, but alleviating the bad taste itself can be done by brushing the teeth, tongue and gums daily; brushing teeth with baking soda and salt; eating saliva-promoting foods such as citrus fruits; using artificial saliva; drinking plenty of water; and eating smaller meals throughout the day if the cause is acid reflux, according to Natural News. Natural News also suggests home remedies such as placing cinnamon or cloves in the mouth and eating peppermints or breath mints.