It’s quite distasteful.
Your last meal is usually to blame if there’s a bad taste lingering in your mouth — but it could also be a sign you’re sick.
So if something’s sour — or stale or rotten or just otherwise gross — read on to see what infections and illnesses might be brewing.
Flu or cold
This year’s “super flu,” a winter cold or even “Christmas tree syndrome” worsening your allergies can all affect your taste buds.
It’s all thanks to post-nasal drip leaving bacteria — and mucus — behind in your throat. Meanwhile, inflammation can dull your palate.
That bitter flavor on your tongue could also be explained by specific proteins called cytokines that are released by your immune system when a viral infection attacks it.
COVID
One of the most well-known symptoms of the COVID-19 virus is the way it alters people’s taste buds, with one in four still not regaining their sense of taste.
The virus is thought to affect cells that support the olfactory sensory neurons, or the nerves that help us smell and taste.
It can also cause parageusia, a metallic or distorted perception of taste that can happen in the first few weeks after becoming infected.
Sinusitis
Whether from a cold or allergy, sinus inflammation can cause a load of symptoms like facial pain, discharge, cough and a funky aftertaste.
That’s because, similar to a cold or COVID, the infected mucus drains down the back of the throat and collects on your tongue, leading to a possible gross taste or even bad breath.
Tonsillitis
Common colds aren’t the only suspect. You may want to check your teeth for more than just spinach caught in between.
Inflammation of the tonsils (the lumps of tissue at the back of the throat) caused by infection can release gases that taste like sulfur or rotting eggs. It can also cause bad breath, sore throat, fever and trouble or painful swallowing.
Gum disease
Yet another reason not to skimp on flossing.
If you’re persistently tasting bad, metallic or bitter flavors, you could have gum disease, or the infection and inflammation of the tissues surrounding and supporting your teeth.
Also called periodontal disease, it’s often caused by poor brushing or flossing habits that let plaque build up and harden.
While it can start out as red, swollen and even bleeding gums, this infection can cause gross-smelling breath from the sulfur compounds produced when left untreated.
Oral thrush
Not just your teeth and gums are responsible for a rancid taste.
Oral thrush, a yeast infection of the mouth, may be difficult to recognize at first. But one telltale sign besides gross tastes is creamy white patches on the tongue and cheeks.
Differing from other causes, this can lead to more of a sour, bitter or even “cottony” feeling in the mouth, as well as fever and trouble swallowing.
