Maradona was undergoing routine examinations in his homeland before returning to Mexico, where he is coach of second division side Dorados de Sinaloa, when doctors discovered the problem.
Argentine sports newspaper Ole said the former Boca Juniors, Napoli and Barcelona midfielder, who led his country to the 1986 World Cup title, would have an endoscopy at a clinic in Olivos, on the outskirts of the capital Buenos Aires.
The severity of his condition was not known and the hospital has made no official statement.
The scare was the latest for Maradona, who has suffered frequent hospital stays over the years, often due to the extravagant lifestyle that helped make him one of the most admired and iconic footballers of the 20th century.
He last fell ill at the 2018 World Cup in Russia, where he was filmed passing out in an executive box at the Argentina-Nigeria game. Argentina won 2-1 to reach the last 16, where they were knocked out of the tournament by eventual winners France.
Maradona, who is now 58, was hospitalised in 2004 with severe heart and respiratory problems linked to cocaine use. He later underwent drug rehabilitation in Cuba and Argentina before a stomach-stapling operation in 2005 helped him lose weight.
In 2007 he checked himself into a clinic in Buenos Aires to help him overcome alcohol abuse problems.
In recent months he has walked with the aid of crutches due to problems with his knees.
The unexpected news of his admittance to hospital came just hours after Maradona’s lawyer confirmed he would coach in Mexico for a second consecutive season.
Maradona took over at the struggling club in September and got them to the playoffs where they lost to Atletico San Luis.
"Diego Maradona has arranged to continue with the Dorados de Sinaloa and will stay as coach of the team for the whole season," his agent Matias Morla wrote on twitter.