As a child, Meghan Swann had suffered several bouts of strep throat, and when she was a teenager, she thought she felt another one coming on. The main symptom was familiar — a dull sore-throat pain.

But this time something was different; there seemed to be a foreign object stuck in the back of her throat, something she couldn’t quite swallow. “So I pushed on my tonsil, and something popped out,” Swann said. The yellowish object was about the size of a piece of gravel and had the sulfurous odour of bad breath. “I thought it was a piece of food or something,” she said.

From then on, Swann, engaged in a secret ritual: popping the mushrooming bits of debris out of her tonsils with a cotton swab whenever they got big enough to cause discomfort.

One day, she mentioned her problem to her mother — and was surprised at the knowing response. Those squishy little things were tonsil stones, her mother explained, and she sometimes got them too.

Formally known as tonsilloliths, the stones consist of mucus, dead cells and other debris that collect in the deep pockets of the tonsils and gradually condense into small, light-colored globs. Bacteria feed on this accumulated matter, giving rise to the odour. Most commonly, the stones are no bigger than a pencil eraser, although doctors have reported individual cases of patients with stones more than an inch wide.

Indeed, tonsil stones appear to be a widespread affliction. In a 2007 study, French researchers found that in a sample of 515 CT scans, 31 subjects — about 6 per cent — showed evidence of calcified matter in their nasopharyngeal tonsils, better known as adenoids.

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