While bad breath happens to the best of us, sometimes standard brushing and flossing just doesn’t cut it, and dentists that we spoke to said this could be a sign of something else, lurking in the back of your throat.

Dr. Ilon Choai, a Miami-based dentist and founder of oral care brand NOBS by biöm, said that tonsil stones, which are small calcifications that form when debris like food particles, dead cells, and bacteria get trapped in the grooves of the tonsils, are “a well-documented source of bad breath.”

“Bacteria and sulfur-producing compounds that accumulate in the stones cause a distinctly foul odor,” he said.

Choai said that if you notice breath that doesn’t improve with brushing or mouthwash, a persistent foreign-body sensation in the throat, or visible white stones in the mirror, then there’s a good chance you have tonsil stones. Red, inflamed, and irritated tonsils are another indicator, according to Choai.

Choai, along with several other dentists that we spoke to, assured us that manual at-home removal options exist, but very few people have the dexterity to remove them effectively, and even then, overcoming the gag reflex is another challenge.