In the first Harry Potter novel, Professor Severus Snape hopes to embarrass Harry by quizzing him on the topic of bezoars. According to Snape, they are stony masses found in the stomach of a goat that can act as an antidote for most poisons. Later in the series, bezoars come to the rescue of a poisoned Ron Weasley.

The name bezoar is a derivative of both the Persian and Arabic languages, translating as “antidote” and “against poisons” – which is probably where J.K. Rowling got her inspiration.

But many Harry Potter readers may not have realised that bezoars aren’t just a product of Rowling’s imagination. And while it’s true they can be found in the stomachs of goats and other animals , humans can also develop bezoars – albeit rarely – in their stomachs, intestines, gullets and even windpipes . Bezoars range in size and weight.

In July 2024 , a 16-inch mass of hair, weighing two pounds, was surgically removed from a 24-year-old woman’s stomach in Manabi, Ecuador. In March 2024, doctors in Newcastle removed a 6-inch hairball from the stomach of a seven-year-old girl. According to reports, it covered 80% of her bowel .

Bezoars are often stony in their appearance, and can be made up of any material that won’t be digested and absorbed through the gut wall. As a result, the material accumulates inside the lumen – the hollow space – of the gut, gradually increasing in size. It takes certain conditions for someone to develop a bezoar – usually eating ind.