You may have heard of Synsepalum dulcificum, the West African “miracle berry” that tricks your tastebuds into thinking sour food is sweet; it’s been a staple at flavor-tripping parties for years, and now has a sleek new image, thanks to the company mberry. But it’s potential is far greater: in addition to serving as a low-calorie sugar substitute, it’s also being used to help chemotherapy patients regain their appetite. Turns out the temporary sweetening—enabled by a protein called miraculin—also counteracts the “everything tastes metallic” side-effect commonly associated with the treatment.