Undigested fruit, chewing gum and hair – the stony masses that might be growing in your stomach

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…