Hanahaki Disease (花吐き病 (Japanese); 하나하키병 (Korean); 花吐病(Chinese)) is a fictional disease in which the victim coughs up flower petals when they suffer from one-sided love. It ends when the beloved returns their feelings (romantic love only; strong friendship is not enough), or when the victim dies. It can be cured through surgical removal, but when the infection is removed, the victim's romantic feelings for their love also disappear.

The term hanahaki comes from the Japanese words hana (花), which means "flower", and hakimasu (吐きます), which means "to throw up".