The 87-year-old Colombian writer is suffering from dehydration and is being treated for a lung and urinary tract infection, said officials from Mexico's Ministry of Health.
García Márquez, who wrote One Hundred Years of Solitude and Love in the time of Cholera is considered one of the most important novelists of the 20th century.
The presidents of both Mexico and Colombia took to social media in support of the ailing writer.
"I wish him a speedy recovery," tweeted Mexican President Enrique Peña.
"All of Colombia wishes a speedy recovery to the greatest of all time: Gabriel García Márquez," tweeted Colombian President Juan Manuel Santos.
Colombia entera le desea una pronta recuperación al más grande de todos los tiempos: Gabriel García Márquez— Juan Manuel Santos (@JuanManSantos) April 3, 2014
[BBC News, CNN]