The star's agent denied press reports on Thursday that the actor was addicted to hard drugs and had only six months to live.
"The report is not only categorically without merit, but it is also impossibly and ridiculously fictitious," said Mr Culkin's spokesman.
"We beseech the responsible media to consider the source and its reputation and to please not perpetuate this destructive and insulting story by pursuing it any further."
America's National Enquirer newspaper reported that Mr Culkin had become addicted to heroin and the powerful prescription painkiller oxycodene following the break-up of a relationship.
It cited an unnamed "close friend" who said the actor was in "downward spiral" and spending $6,000 (£3,863) a month on his drug habit after separating from Mila Kunis, an actress, in 2010.
In February, pictures of Mr Culkin showed the actor looking frail and emaciated leading to speculation over his health.
As a child, Mr Culkin, 31, became a star with his roles in films such as Home Alone (1990) and My Girl (1991).
But his adult career has not been as successful, his last film was five years ago and he currently DJs at clubs in New York.
