The flower shop next door {Oumasai} [Hanahaki AU]

When one's internal organs are exposed to a large amount of pollen, the pollens will start to accumulate into flower seeds that sprout and bloom when the victim feels affection towards someone. As romantic as it may sound, the flowers are parasitic and if not rid of, may continue to coil around the organs on vines, inflicting sharp pain on the heart whenever jealousy or more affection is felt. During the flower's growth, petals will fall out, causing the victim to cough up flower petals which may lead to suffocation. The only way to remove them is to have your feelings returned or by getting them surgically removed. However, by getting them surgically removed, the patient's feelings towards their loved one will also disappear. In some cases, their memory about their loved one may also be lost as a side effect.

Warning: Happily ever after ending might not be included