Dehydration can cause unusual taste in the mouth and is worsened by use of alcohol-containing mouthwashes. Dehydration is common if you are not drinking water frequently throughout the day. You may also be consuming caffeinated (tea, coffee etc) beverages that reduce saliva production.
Very often, concerns over unusual tastes or bad breath cause individuals to seek out mouthrinses that may be strongly flavoured or contain alcohol as the main ingredient. This may further contribute to surface dehydration of the oral mucosa (the lining of the mouth) by removing surface protective glycoproteins deposited by saliva.
Chlorhexidine-containing mouthwashes or gels may be prescribed for certain conditions such as gum disease or to prevent post-operative surgical infections (such as after wisdom tooth surgery). Chlorhexidine is known to cause taste disturbances or dulling of taste sensation in certain individuals after a period of use. If you are using a chlorhexidine-containing product, I would check with your dentist if it is advisable to stop using it.
The taste you are describing could be due to gastric reflux that occurs during the day. Gastric reflux occurs when the muscle that keeps the opening to the stomach closed (the gastric sphincter) is weak and causes leakage of gastric acid up the oesophagus into the back of the mouth. Your dentist may suspect that this is occurring by examining your teeth for signs of acid erosion. I would advise seeing your medical GP to have this managed.
Post-nasal drip, where mucus from the nasal passages drips down the back of the throat can be a source of an unusual taste. Bacteria living in the tonsils and on the surface of the tongue digest the proteins in the mucus producing sulphur compounds that may taste odd.
Salivary stones that occur in the salivary duct or even more rarely, within the salivary gland itself may. These stones may cause infection and if there is pus discharge, this may produce a strange taste. Other types of infections (dental abscesses or gum infections around an impacted wisdom tooth, known as pericoronitis) may also produce pus.
Since there are so many possible causes that could be contributing to your problem, I would see a dentist for a thorough examination to ensure that an effective solution can be found quickly.
