You recovered from COVID. Now your coffee tastes like sewage.

That was in June. Since then, her senses of smell and taste have started to come back—but intermittently and in strange ways. There were the two weeks in the summer when all she could smell was phantom smoke. The odor was so strong that she woke up one morning startled, convinced that something in her house was on fire. Sometime later, she was able to smell her boyfriend’s cologne again—but instead of the familiar scent she had always loved, it was a sickening chemical odor. There’s also the hand soap at work, which used to smell generically fruity to her but now smells exactly, and eerily, like Burger King Whoppers. Martinez used to love Whoppers, but she can’t stand the smell of the soap. Her co-workers find her predicament weird and frankly a little funny. “I’m like, ‘I know! What the heck?’” she told me. “Why does it smell like that? Why can’t it be something good?”…

In the past year, COVID-19 has drawn much more attention to smell loss, also known as anosmia, as well as to the strange ways smell is regained. Some patients go through a period of phantosmia, in which they experience phantom smells, or parosmia, in which they experience distorted smells—like Martinez’s smoke and Whoppers. These odors are quite foul, for reasons that are poorly understood; people find it extremely distressing to drink coffee that smells of sewage or to come out of the shower smelling like trash. “It’s worse than not being able to smell,” says Pamela Dalton, a cognitive psychologist at the Monell Chemical Senses Center. In most cases, the conditions are temporary. But the process of relearning to smell is as mysterious to us as how we lose it.