The body of Padre Pio on display back in 2008. Photo: Getty Images

ITALY'S Padre Pio used carbolic acid to cause bleeding wounds on his hands that he claimed were replicas of Christ's, according to a new book.

Pio, a former monk who died in 1968 aged 81, wore gloves because his hands bled constantly for 50 years in what were revered as stigmata wounds.

He became Italy's most loved saint after he was canonised by Pope John Paul II in 2002.

But a new book has heaped more scorn on the claims that his wounds were duplicates of those suffered by Jesus during the crucifixion.

Italian historian Professor Sergio Luzzatto has discovered documents including a letter from a pharmacist who arranged carbolic acid for Pio.

Professor Luzzatto suggests in Padre Pio: Miracle and Politics in a Secular Age that it was the corrosive acid that caused the bleeding on the saint's hands.

He also said many Popes had expressed doubts and suggested the Vatican only canonised Pio – real name Francesco Forgione – because of public pressure.

"Human beings – and particularly the most fragile among them – will still need to look at figures such as Padre Pio to get, if not miracles, then at least consolation and hope," Professor Luzzatto said, according the the Sun.

Professor Luzzatto previously referred to the documents, found in the Vatican's archive, in The Other Christ: Padre Pio and 19th Century Italy.

His claims were dismissed by the Catholic Anti-Defamation League in 2007.

Pietro Siffi, the president of the League, said at the time: "We would like to remind Mr Luzzatto that according to Catholic doctrine, canonisation carries with it papal infallibility.

"We would like to suggest to Mr Luzzatto that he dedicates his energies to studying religion properly."