Parosmia is a condition that affects the sense of smell, causing familiar odors to be perceived differently, often in an unpleasant way. People with parosmia may find that foods they once enjoyed now smell or taste strange, which can lead to changes in appetite and eating habits. This condition can occur after a viral infection, head injury, or exposure to certain chemicals. The exact cause of parosmia is not fully understood, but it is believed to involve changes in the olfactory system, which is responsible for detecting smells. Treatment options are limited, but some individuals may benefit from smell training or addressing underlying health issues.