The term "Curse" (呪い Noroi) refers to unidentifiable and fatal Gourmet World diseases which have no known cures and can kill victims in less than a month, as such they have received the term "curse" as they are truly ominous and deadly and all those infected will never be cured.
All those infected by a curse will have a visible sign of it on their body, such as an infected eye as seen with the Gourmet Knight, Takimaru, whose left eye is dark in color with a glowing pink pupil and all those who see it immediately recognize its nature as a fatal "curse".
While there is no known medical treatment for a curse, Aimaru, the leader of the Gourmet Knights was able to nullify the fatal effects of a curse that was infecting a young Takimaru by "eating" it through an unknown method. After consuming the fatal disease, Takimaru's life was no longer threatened, but his left eye would forever remain visibly affected by the disease. Despite consuming it, Aimaru himself did not suffer the immediate effects of the curse, having been able to live many years after doing so with only his health becoming worse due to the number of diseases he kept on consuming over the years as part of his doctrine. Aimaru's mysterious method appears to be the only way to nullify the harmful effects of the curse and appears to be the closest thing to a treatment that exists, as even Yosaku, one of the greatest saiseiyas in the world does not have a cure for it either, however he can prepare a unique medicine for a special case like Aimaru's who was weak from consuming the curse along with many other diseases, suggesting that the curse became less untreatable after being consumed by him.