Hanahaki Disease is a fictional illness wherein the victim coughs up flower petals because they have been suffering from one-sided love.
It also has several variations and is used in both happy and tragic stories.
The signs and symptoms of the disease are summed up by intense discomfort, with flowers blooming in the heart and lungs, and then coughing them up.
The only treatment for their condition is for their beloved one to return their emotions, or if the victim dies.
In certain cases, however, “Hanahaki disease” may be cured by surgery, in which romantic feelings of the victim often vanish. In fandoms, it mainly appears in Boys’ Love (fictional male homosexual romance) fanfictions.
The term “hanakini” comes from the Japanese words “hana”, which means “flower”, and “hakimasu”, which means “to throw up”.
“Hanahaki disease” has been popularized in animes, mangas and other similar media in East Asia (Korea, Japan, China) and has only been used by Westerners for a few years.
The “Hanahaki disease” trope was popularized by shoujo manga (category of manga/anime marketed to girls), such as The Girl Who Spit Flowers by Naoko Matsuda, which was released in 2009.
However, its exact and true origins are unknown.
The concept of the “Hanahaki disease” started to spread outside of the fandoms as well – many people liked the idea behind it and created non-fannish art, like music, poetry, etc.
However, “Hanahaki” disease is especially common within fandom due to its propensity for discomfort, pain / comfort and overall romantic tension.