Tonsil stones, also known as tonsilloliths, are typically caused when food particles, saliva, and mucus get trapped in the small crevices of your tonsils. Over time, these particles harden and calcify, forming what many describe as small, rock-like formations. According to the Mayo Clinic, the process is gradual, and while they often go unnoticed, tonsil stones can lead to discomfort and unpleasant symptoms such as a sore throat, difficulty swallowing, coughing, persistent bad breath, and a bad taste in the mouth.